Zdenek Dvorak - [patch] Predictive commoning, updated (original) (raw)

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From: Zdenek Dvorak
To: gcc-patches at gcc dot gnu dot org
Cc: richard dot guenther at gmail dot com
Date: Wed, 14 Feb 2007 23:29:20 +0100
Subject: [patch] Predictive commoning, updated

Hello,

the updated version of the predictive commoning patch, with some additional changes:

Index: passes.c
*** passes.c (revision 120837) --- passes.c (working copy) *************** init_optimization_passes (void) *** 581,586 **** --- 581,588 ---- NEXT_PASS (pass_pre); NEXT_PASS (pass_may_alias); NEXT_PASS (pass_sink_code);

NEXT_PASS (pass_dominator);

NEXT_PASS (pass_dce); NEXT_PASS (pass_tree_loop); NEXT_PASS (pass_cse_reciprocals); NEXT_PASS (pass_reassoc);

uh - another DOM pass? What happens if you omit this hunk completely?

PRE creates lots of opportunities for copy propagation and other cleanups, and the dead code created by these cleanups may confuse some parts of the predictive commoning (especially finding opportunities for reassociation). The copy propagation pass at the begining of the loop optimizer seems to be sufficient, though, so only the dceloop pass needs to be scheduled.

added documentation changes
predictive commoning is only enabled at -O3
the SSA_NAME_OCCURS_IN_ABNORMAL_PHI is removed. On most testcases (in particular, in mgrid), it did not help much, anyway.

I did not change the position of the predictive commoning pass, as the vectorizer people asked, since that does not fix the vectorizer problem anyway (as PRE does some trivial predictive commoning as well).

Bootstrapped & regtested on i686 and x86_64.

Zdenek

* doc/passes.texi: Document predictive commoning.
* doc/invoke.texi (-fpredictive-commoning): Document.
* opts.c (decode_options): Enable flag_predictive_commoning on -O3.
* tree-ssa-loop-im.c (get_lsm_tmp_name): Export.  Allow
adding indices to the generated name.
(schedule_sm): Pass 0 to get_lsm_tmp_name.
* tree-ssa-loop-niter.c (stmt_dominates_stmt_p): Export.
* tree-pretty-print.c (op_symbol_1): Renamed to ...
(op_symbol_code): ... and exported.
(dump_omp_clause, op_symbol): Use op_symbol_code
instead of op_symbol_1.
* tree-pass.h (pass_predcom): Declare.
* timevar.def (TV_PREDCOM): New timevar.
* tree-ssa-loop.c (run_tree_predictive_commoning,
gate_tree_predictive_commoning, pass_predcom): New.
* tree-data-ref.c (find_data_references_in_loop): Find the
references in dominance order.
* tree-affine.c: Include tree-gimple.h and hashtab.h.
(aff_combination_find_elt, name_expansion_hash,
name_expansion_eq, tree_to_aff_combination_expand,
double_int_constant_multiple_p, aff_combination_constant_multiple_p):
New functions.
* tree-affine.h (aff_combination_constant_multiple_p,
tree_to_aff_combination_expand): Declare.
* tree-predcom.c: New file.
* common.opt (fpredictive-commoning): New option.
* tree-flow.h (op_symbol_code, tree_predictive_commoning,
stmt_dominates_stmt_p, get_lsm_tmp_name): Declare.
* Makefile.in (tree-predcom.o): Add.
(tree-affine.o): Add TREE_GIMPLE_H dependency.
* passes.c (init_optimization_passes):  Add dceloop after
copy propagation in loop optimizer.  Add predictive commoning
to loop optimizer passes.

* gcc.dg/tree-ssa/predcom-1.c: New test.
* gcc.dg/tree-ssa/predcom-2.c: New test.
* gcc.dg/tree-ssa/predcom-3.c: New test.
* gcc.dg/tree-ssa/predcom-4.c: New test.
* gcc.dg/tree-ssa/predcom-5.c: New test.
* gcc.dg/vect/dump-tree-dceloop-pr26359.c: Test dceloop2 dumps.

* tree-data-ref.c (get_ptr_tag): New function.
(ptr_decl_may_alias_p, ptr_ptr_may_alias_p): Take subvars
and alias sets into account.
(object_analysis): Use get_ptr_tag.

Index: doc/passes.texi

* doc/passes.texi (revision 121952) --- doc/passes.texi (working copy) *********** This pass completely unrolls loops with * 602,607 **** --- 602,618 ---- is located in @file{tree-ssa-loop-ivcanon.c} and described by @code{pass_complete_unroll}.
+ @item Predictive commoning + + This pass makes the code reuse the computations from the previous + iterations of the loops, especially loads and stores to memory. + It does so by storing the values of these computations to a bank + of temporary variables that are rotated at the end of loop. To avoid + the need for this rotation, loop is then unrolled and the copies + of the loop body are rewritten to use the appropriate version of + the temporary variable. This pass is located in @file{tree-predcom.c} + and described by @code{pass_predcom}. + @item Array prefetching
This pass issues prefetch instructions for array references inside Index: doc/invoke.texi

* doc/invoke.texi (revision 121952) --- doc/invoke.texi (working copy) *********** Objective-C and Objective-C++ Dialects}. * 329,335 -ffinite-math-only -fno-signed-zeros @gol -fno-toplevel-reorder -fno-trapping-math -fno-zero-initialized-in-bss @gol -fomit-frame-pointer -foptimize-register-move @gol ! -foptimize-sibling-calls -fprefetch-loop-arrays @gol -fprofile-generate -fprofile-use @gol -fregmove -frename-registers @gol -freorder-blocks -freorder-blocks-and-partition -freorder-functions @gol --- 329,335 ---- -ffinite-math-only -fno-signed-zeros @gol -fno-toplevel-reorder -fno-trapping-math -fno-zero-initialized-in-bss @gol -fomit-frame-pointer -foptimize-register-move @gol ! -foptimize-sibling-calls -fpredictive-commoning -fprefetch-loop-arrays @gol -fprofile-generate -fprofile-use @gol -fregmove -frename-registers @gol -freorder-blocks -freorder-blocks-and-partition -freorder-functions @gol ********* invoking @option{-O2} on programs that u * 4807,4813 @opindex O3 Optimize yet more. @option{-O3} turns on all optimizations specified by @option{-O2} and also turns on the @option{-finline-functions}, ! @option{-funswitch-loops} and @option{-fgcse-after-reload} options.
@item -O0 @opindex O0 --- 4807,4814 ---- @opindex O3 Optimize yet more. @option{-O3} turns on all optimizations specified by @option{-O2} and also turns on the @option{-finline-functions}, ! @option{-funswitch-loops}, @option{-fpredictive-commoning} and ! @option{-fgcse-after-reload} options.
@item -O0 @opindex O0 ********* This optimization is enabled by default. * 5519,5524 **** --- 5520,5533 ---- With this option, the compiler will create multiple copies of some local variables when unrolling a loop which can result in superior code.
+ @item -fpredictive-commoning + @opindex fpredictive-commoning + Perform predictive commoning optimization, i.e., reusing computations + (especially memory loads and stores) performed in the previous + iterations of loops. + + This option is enabled at level @option{-O3}. + @item -fprefetch-loop-arrays @opindex fprefetch-loop-arrays If supported by the target machine, generate instructions to prefetch Index: tree-ssa-loop-im.c

* tree-ssa-loop-im.c (revision 121952) --- tree-ssa-loop-im.c (working copy) *********** gen_lsm_tmp_name (tree ref) * 1002,1015 **** }
/* Determines name for temporary variable that replaces REF. ! The name is accumulated into the lsm_tmp_name variable. /
! static char * ! get_lsm_tmp_name (tree ref) { lsm_tmp_name_length = 0; gen_lsm_tmp_name (ref); lsm_tmp_name_add ("_lsm"); return lsm_tmp_name; }
--- 1002,1024 ---- }
/ Determines name for temporary variable that replaces REF. ! The name is accumulated into the lsm_tmp_name variable. ! N is added to the name of the temporary. /
! char ! get_lsm_tmp_name (tree ref, unsigned n) { + char ns[2]; + lsm_tmp_name_length = 0; gen_lsm_tmp_name (ref); lsm_tmp_name_add ("_lsm"); + if (n < 10) + { + ns[0] = '0' + n; + ns[1] = 0; + lsm_tmp_name_add (ns); + } return lsm_tmp_name; }
*************** schedule_sm (struct loop loop, VEC (edg 1039,1045 ** }
tmp_var = make_rename_temp (TREE_TYPE (ref), ! get_lsm_tmp_name (ref));
fmt_data.loop = loop; fmt_data.orig_loop = loop; --- 1048,1054 ---- }
tmp_var = make_rename_temp (TREE_TYPE (ref), ! get_lsm_tmp_name (ref, ~0));
fmt_data.loop = loop; fmt_data.orig_loop = loop; Index: tree-ssa-loop-niter.c

* tree-ssa-loop-niter.c (revision 121952) --- tree-ssa-loop-niter.c (working copy) *********** estimate_numbers_of_iterations (void) * 2032,2038 ****
/* Returns true if statement S1 dominates statement S2. /
! static bool stmt_dominates_stmt_p (tree s1, tree s2) { basic_block bb1 = bb_for_stmt (s1), bb2 = bb_for_stmt (s2); --- 2032,2038 ----
/ Returns true if statement S1 dominates statement S2. */
! bool stmt_dominates_stmt_p (tree s1, tree s2) { basic_block bb1 = bb_for_stmt (s1), bb2 = bb_for_stmt (s2); Index: tree-pretty-print.c

* tree-pretty-print.c (revision 121952) --- tree-pretty-print.c (working copy) *********** Software Foundation, 51 Franklin Street, * 37,43 ****
/* Local functions, macros and variables. / static int op_prio (tree); - static const char op_symbol_1 (enum tree_code); static const char op_symbol (tree); static void pretty_print_string (pretty_printer , const char); static void print_call_name (pretty_printer , tree); --- 37,42 ---- ************* dump_omp_clause (pretty_printer buffer, * 296,302
case OMP_CLAUSE_REDUCTION: pp_string (buffer, "reduction("); ! pp_string (buffer, op_symbol_1 (OMP_CLAUSE_REDUCTION_CODE (clause))); pp_character (buffer, ':'); dump_generic_node (buffer, OMP_CLAUSE_DECL (clause), spc, flags, false); --- 295,301 ----
case OMP_CLAUSE_REDUCTION: pp_string (buffer, "reduction("); ! pp_string (buffer, op_symbol_code (OMP_CLAUSE_REDUCTION_CODE (clause))); pp_character (buffer, ':'); dump_generic_node (buffer, OMP_CLAUSE_DECL (clause), spc, flags, false); ********* op_prio (tree op) * 2346,2355 **** }

! / Return the symbol associated with operator OP. /
! static const char * ! op_symbol_1 (enum tree_code code) { switch (code) { --- 2345,2354 ---- }

! / Return the symbol associated with operator CODE. /
! const char * ! op_symbol_code (enum tree_code code) { switch (code) { ************* op_symbol_1 (enum tree_code code) * 2513,2522 **** } }
static const char * op_symbol (tree op) { ! return op_symbol_1 (TREE_CODE (op)); }
/ Prints the name of a CALL_EXPR. / --- 2512,2523 ---- } }
+ / Return the symbol associated with operator OP. / + static const char * op_symbol (tree op) { ! return op_symbol_code (TREE_CODE (op)); }
/ Prints the name of a CALL_EXPR. */ Index: tree-pass.h

* tree-pass.h (revision 121952) --- tree-pass.h (working copy) *********** extern struct tree_opt_pass pass_tree_lo * 247,252 **** --- 247,253 ---- extern struct tree_opt_pass pass_tree_loop_init; extern struct tree_opt_pass pass_lim; extern struct tree_opt_pass pass_tree_unswitch; + extern struct tree_opt_pass pass_predcom; extern struct tree_opt_pass pass_iv_canon; extern struct tree_opt_pass pass_scev_cprop; extern struct tree_opt_pass pass_empty_loop; Index: testsuite/gcc.dg/tree-ssa/predcom-3.c

* testsuite/gcc.dg/tree-ssa/predcom-3.c (revision 0) --- testsuite/gcc.dg/tree-ssa/predcom-3.c (revision 0) *********** * 0 **** --- 1,16 ---- + /* { dg-do compile } / + / { dg-options "-O2 -fpredictive-commoning -fdump-tree-pcom-details" } / + + int a[1000], b[1000]; + + void test(void) + { + int i; + + for (i = 1; i < 999; i++) + b[i] = (a[i + 1] + a[i] + a[i - 1]) / 3; + } + + / Verify that we used 3 temporary variables for the loop. / + / { dg-final { scan-tree-dump-times "Unrolling 3 times." 1 "pcom"} } / + / { dg-final { cleanup-tree-dump "pcom" } } */ Index: testsuite/gcc.dg/tree-ssa/predcom-4.c

* testsuite/gcc.dg/tree-ssa/predcom-4.c (revision 0) --- testsuite/gcc.dg/tree-ssa/predcom-4.c (revision 0) *********** * 0 **** --- 1,30 ---- + /* { dg-do compile } / + / { dg-do run } / + / { dg-options "-O2 -fpredictive-commoning -fdump-tree-pcom-details" } / + + / Test for predictive commoning of expressions, without reassociation. / + + void abort (void); + + int a[1000], b[1000], c[1000]; + + int main(void) + { + int i; + + for (i = 0; i < 1000; i++) + a[i] = b[i] = i; + + for (i = 1; i < 998; i++) + c[i] = a[i + 2] * b[i + 1] - b[i - 1] * a[i]; + + for (i = 1; i < 998; i++) + if (c[i] != 4 * i + 2) + abort (); + + return 0; + } + + / { dg-final { scan-tree-dump-times "Combination" 1 "pcom"} } / + / { dg-final { scan-tree-dump-times "Unrolling 3 times." 1 "pcom"} } / + / { dg-final { cleanup-tree-dump "pcom" } } */ Index: testsuite/gcc.dg/tree-ssa/predcom-5.c

* testsuite/gcc.dg/tree-ssa/predcom-5.c (revision 0) --- testsuite/gcc.dg/tree-ssa/predcom-5.c (revision 0) *********** * 0 **** --- 1,30 ---- + /* { dg-do compile } / + / { dg-do run } / + / { dg-options "-O2 -fpredictive-commoning -fdump-tree-pcom-details" } / + + / Test for predictive commoning of expressions, with reassociation. / + + void abort (void); + + unsigned a[1000], b[1000], c[1000], d[1000]; + + int main(void) + { + unsigned i; + + for (i = 0; i < 1000; i++) + a[i] = b[i] = d[i] = i; + + for (i = 1; i < 998; i++) + c[i] = d[i + 1] * a[i + 2] * b[i + 1] - b[i - 1] * a[i] * d[i - 1]; + + for (i = 1; i < 998; i++) + if (c[i] != (i+1)(i+2)(i+1) - (i - 1) i * (i - 1)) + abort (); + + return 0; + } + + /* { dg-final { scan-tree-dump-times "Combination" 2 "pcom"} } / + / { dg-final { scan-tree-dump-times "Unrolling 3 times." 1 "pcom"} } / + / { dg-final { cleanup-tree-dump "pcom" } } */ Index: testsuite/gcc.dg/tree-ssa/predcom-1.c

* testsuite/gcc.dg/tree-ssa/predcom-1.c (revision 0) --- testsuite/gcc.dg/tree-ssa/predcom-1.c (revision 0) *********** * 0 **** --- 1,49 ---- + /* { dg-do compile } / + / { dg-do run } / + / { dg-options "-O2 -fpredictive-commoning -fdump-tree-pcom-details" } / + + void abort (void); + + unsigned fib[1000]; + + void count_fib(void) + { + int i; + + fib[0] = 0; + fib[1] = 1; + for (i = 2; i < 1000; i++) + fib[i] = (fib[i-1] + fib[i - 2]) & 0xffff; + } + + unsigned avg[1000]; + + void count_averages(int n) + { + int i; + + for (i = 1; i < n; i++) + avg[i] = ((fib[i - 1] + fib[i] + fib[i + 1]) / 3) & 0xffff; + } + + int main(void) + { + count_fib (); + count_averages (999); + + if (fib[19] != 4181 || avg[19] != 4510) + abort (); + + if (fib[999] != 162 || avg[998] != 21953) + abort (); + + return 0; + } + + / Verify that both loops were transformed and unrolled. / + / { dg-final { scan-tree-dump-times "Unrolling 2 times." 2 "pcom"} } / + + / Also check that we undid the transformation previously made by PRE. / + / { dg-final { scan-tree-dump-times "looparound ref" 1 "pcom"} } / + + / { dg-final { cleanup-tree-dump "pcom" } } */ Index: testsuite/gcc.dg/tree-ssa/predcom-2.c

* testsuite/gcc.dg/tree-ssa/predcom-2.c (revision 0) --- testsuite/gcc.dg/tree-ssa/predcom-2.c (revision 0) *********** * 0 **** --- 1,42 ---- + /* { dg-do compile } / + / { dg-do run } / + / { dg-options "-O2 -fpredictive-commoning -fdump-tree-pcom-details" } / + + void abort (void); + + int fib[1000]; + + void count_fib(void) + { + int i; + + fib[0] = 0; + fib[1] = 1; + for (i = 2; i < 1000; i++) + fib[i] = fib[i-1] + fib[i - 2]; + } + + int avg[1000]; + + void count_averages(void) + { + int i; + + for (i = 1; i < 999; i++) + avg[i] = (fib[i - 1] + fib[i] + fib[i + 1]) / 3; + } + + int main(void) + { + count_fib (); + count_averages (); + + if (fib[19] != 4181 || avg[19] != 4510) + abort (); + + return 0; + } + + / Verify that both loops were transformed and unrolled. / + / { dg-final { scan-tree-dump-times "Unrolling 2 times." 2 "pcom"} } / + / { dg-final { cleanup-tree-dump "pcom" } } */ Index: testsuite/gcc.dg/vect/dump-tree-dceloop-pr26359.c

* testsuite/gcc.dg/vect/dump-tree-dceloop-pr26359.c (revision 121952) --- testsuite/gcc.dg/vect/dump-tree-dceloop-pr26359.c (working copy) *********** foo () { * 11,16 **** } }
! /* { dg-final { scan-tree-dump-times "Deleting : vect_" 0 "dceloop" } } / ! / { dg-final { cleanup-tree-dump "dceloop" } } / / { dg-final { cleanup-tree-dump "vect" } } / --- 11,16 ---- } }
! / { dg-final { scan-tree-dump-times "Deleting : vect_" 0 "dceloop2" } } / ! / { dg-final { cleanup-tree-dump "dceloop2" } } / / { dg-final { cleanup-tree-dump "vect" } } */ Index: opts.c

* opts.c (revision 121952) --- opts.c (working copy) *********** decode_options (unsigned int argc, const * 501,506 **** --- 501,507 ----
if (optimize >= 3) { + flag_predictive_commoning = 1; flag_inline_functions = 1; flag_unswitch_loops = 1; flag_gcse_after_reload = 1; Index: timevar.def

* timevar.def (revision 121952) --- timevar.def (working copy) *********** DEFTIMEVAR (TV_TREE_VECTORIZATION , " * 111,116 **** --- 111,117 ---- DEFTIMEVAR (TV_TREE_LINEAR_TRANSFORM , "tree loop linear") DEFTIMEVAR (TV_TREE_PREFETCH , "tree prefetching") DEFTIMEVAR (TV_TREE_LOOP_IVOPTS , "tree iv optimization") + DEFTIMEVAR (TV_PREDCOM , "predictive commoning") DEFTIMEVAR (TV_TREE_LOOP_INIT , "tree loop init") DEFTIMEVAR (TV_TREE_LOOP_FINI , "tree loop fini") DEFTIMEVAR (TV_TREE_CH , "tree copy headers") Index: tree-ssa-loop.c

* tree-ssa-loop.c (revision 121952) --- tree-ssa-loop.c (working copy) *********** struct tree_opt_pass pass_tree_unswitch * 175,180 **** --- 175,216 ---- 0 /* letter / };
+ / Predictive commoning. / + + static unsigned + run_tree_predictive_commoning (void) + { + if (!current_loops) + return 0; + + tree_predictive_commoning (); + return 0; + } + + static bool + gate_tree_predictive_commoning (void) + { + return flag_predictive_commoning != 0; + } + + struct tree_opt_pass pass_predcom = + { + "pcom", / name / + gate_tree_predictive_commoning, / gate / + run_tree_predictive_commoning, / execute / + NULL, / sub / + NULL, / next / + 0, / static_pass_number / + TV_PREDCOM, / tv_id / + PROP_cfg, / properties_required / + 0, / properties_provided / + 0, / properties_destroyed / + 0, / todo_flags_start / + TODO_dump_func | TODO_verify_loops + | TODO_update_ssa_only_virtuals, / todo_flags_finish / + 0 / letter / + }; + / Loop autovectorization. */
static unsigned int Index: tree-data-ref.c

* tree-data-ref.c (revision 121952) --- tree-data-ref.c (working copy) ************* static struct data_reference * init_data * 132,137 ** --- 132,155 ---- static bool subscript_dependence_tester_1 (struct data_dependence_relation , struct data_reference , struct data_reference ); + static void free_data_ref (data_reference_p); + + / Returns tag for PTR (a ssa name). If SYMBOL_ONLY is true, only SMT may be + returned. / + + static tree + get_ptr_tag (tree ptr, bool symbol_only) + { + tree tag = NULL_TREE; + + gcc_assert (TREE_CODE (ptr) == SSA_NAME); + if (!symbol_only && SSA_NAME_PTR_INFO (ptr)) + tag = SSA_NAME_PTR_INFO (ptr)->name_mem_tag; + if (!tag) + tag = symbol_mem_tag (SSA_NAME_VAR (ptr)); + + return tag; + }
/ Determine if PTR and DECL may alias, the result is put in ALIASED. Return FALSE if there is no symbol memory tag for PTR. */ ************* ptr_decl_may_alias_p (tree ptr, tree dec * 142,198 **** bool aliased) { tree tag = NULL_TREE; - struct ptr_info_def pi = DR_PTR_INFO (ptr_dr);

gcc_assert (TREE_CODE (ptr) == SSA_NAME && DECL_P (decl));
! if (pi) ! tag = pi->name_mem_tag; ! if (!tag) ! tag = symbol_mem_tag (SSA_NAME_VAR (ptr)); if (!tag) tag = DR_MEMTAG (ptr_dr); if (!tag) return false; !
! *aliased = is_aliased_with (tag, decl);
return true; }

/* Determine if two pointers may alias, the result is put in ALIASED. Return FALSE if there is no symbol memory tag for one of the pointers. /
static bool ! ptr_ptr_may_alias_p (tree ptr_a, tree ptr_b, struct data_reference dra, struct data_reference drb, bool aliased) {
! tree tag_a = NULL_TREE, tag_b = NULL_TREE; ! struct ptr_info_def pi_a = DR_PTR_INFO (dra);
! struct ptr_info_def pi_b = DR_PTR_INFO (drb);

! if (pi_a && pi_a->name_mem_tag && pi_b && pi_b->name_mem_tag) ! { ! tag_a = pi_a->name_mem_tag; ! tag_b = pi_b->name_mem_tag; ! } ! else { ! tag_a = symbol_mem_tag (SSA_NAME_VAR (ptr_a)); ! if (!tag_a) ! tag_a = DR_MEMTAG (dra); ! if (!tag_a) ! return false; !
! tag_b = symbol_mem_tag (SSA_NAME_VAR (ptr_b)); ! if (!tag_b) ! tag_b = DR_MEMTAG (drb); ! if (!tag_b) ! return false; } ! aliased = (tag_a == tag_b); return true; }
--- 160,228 ---- bool aliased) { tree tag = NULL_TREE;
gcc_assert (TREE_CODE (ptr) == SSA_NAME && DECL_P (decl));
! tag = get_ptr_tag (ptr, false); if (!tag) tag = DR_MEMTAG (ptr_dr); if (!tag) return false; !
! aliased = is_aliased_with (tag, decl); ! if (var_can_have_subvars (decl)) ! { ! subvar_t sv; !
! for (sv = get_subvars_for_var (decl); sv; sv = sv->next) ! aliased |= is_aliased_with (tag, sv->var); ! } return true; }
/ Determine if two pointers may alias, the result is put in ALIASED. Return FALSE if there is no symbol memory tag for one of the pointers. /
static bool ! ptr_ptr_may_alias_p (tree ptr_a, tree ptr_b, struct data_reference dra, struct data_reference drb, bool aliased) {
! tree tag_a, tag_b; ! bitmap bal1, bal2;
! tag_a = get_ptr_tag (ptr_a, false); ! if (!tag_a) ! tag_a = DR_MEMTAG (dra); ! if (!tag_a) ! return false; ! ! tag_b = get_ptr_tag (ptr_b, false); ! if (!tag_b) ! tag_b = DR_MEMTAG (drb); ! if (!tag_b) ! return false; ! ! if (tag_a == tag_b) { ! aliased = true; ! return true; } ! ! bal1 = BITMAP_ALLOC (NULL); ! bitmap_set_bit (bal1, DECL_UID (tag_a)); ! if (MTAG_P (tag_a) && MTAG_ALIASES (tag_a)) ! bitmap_ior_into (bal1, MTAG_ALIASES (tag_a)); ! ! bal2 = BITMAP_ALLOC (NULL); ! bitmap_set_bit (bal2, DECL_UID (tag_b)); ! if (MTAG_P (tag_b) && MTAG_ALIASES (tag_b)) ! bitmap_ior_into (bal2, MTAG_ALIASES (tag_b)); ! *aliased = bitmap_intersect_p (bal1, bal2); ! ! BITMAP_FREE (bal1); ! BITMAP_FREE (bal2); return true; }
************* object_analysis (tree memref, tree stmt, * 1772,1780 **** switch (TREE_CODE (base_address)) { case SSA_NAME: ! memtag = symbol_mem_tag (SSA_NAME_VAR (base_address)); ! if (!(memtag) && TREE_CODE (TREE_OPERAND (memref, 0)) == SSA_NAME) ! memtag = symbol_mem_tag (SSA_NAME_VAR (TREE_OPERAND (memref, 0))); break; case ADDR_EXPR: memtag = TREE_OPERAND (base_address, 0); --- 1802,1810 ---- switch (TREE_CODE (base_address)) { case SSA_NAME: ! memtag = get_ptr_tag (base_address, true); ! if (!memtag && TREE_CODE (TREE_OPERAND (memref, 0)) == SSA_NAME) ! memtag = get_ptr_tag (TREE_OPERAND (memref, 0), true); break; case ADDR_EXPR: memtag = TREE_OPERAND (base_address, 0); ************* find_data_references_in_loop (struct loo * 4355,4361 **** unsigned int i; block_stmt_iterator bsi;
! bbs = get_loop_body (loop);
for (i = 0; i < loop->num_nodes; i++) { --- 4385,4391 ---- unsigned int i; block_stmt_iterator bsi;
! bbs = get_loop_body_in_dom_order (loop);
for (i = 0; i < loop->num_nodes; i++) { Index: tree-affine.c

* tree-affine.c (revision 121952) --- tree-affine.c (working copy) *********** Software Foundation, 51 Franklin Street, * 30,35 **** --- 30,37 ---- #include "diagnostic.h" #include "tree-dump.h" #include "tree-affine.h" + #include "tree-gimple.h" + #include "hashtab.h"
/* Extends CST as appropriate for the affine combinations COMB. */
*************** aff_combination_mult (aff_tree c1, aff_ 493,495 ** --- 495,699 ---- aff_combination_add_product (c1, double_int_one, c2->rest, r); aff_combination_add_product (c1, c2->offset, NULL, r); } + + /* Returns the element of COMB whose value is VAL, or NULL if no such + element exists. If IDX is not NULL, it is set to the index of VAL in + COMB. / +
+ static struct aff_comb_elt + aff_combination_find_elt (aff_tree comb, tree val, unsigned idx) + { + unsigned i; + + for (i = 0; i < comb->n; i++) + if (operand_equal_p (comb->elts[i].val, val, 0)) + { + if (idx) + idx = i; + + return &comb->elts[i]; + } + + return NULL; + } + + / Element of the cache that maps ssa name NAME to its expanded form + as an affine expression EXPANSION. / + + struct name_expansion + { + aff_tree expansion; + tree name; + + / True if the expansion for the name is just being generated. / + unsigned in_progress : 1; + }; + + / Hash function for struct name_expansion. / + + static hashval_t + name_expansion_hash (const void e) + { + return SSA_NAME_VERSION (((struct name_expansion ) e)->name); + } + + / Equality function for struct name_expansion. The second argument is an + SSA name. / + + static int + name_expansion_eq (const void e, const void n) + { + return ((struct name_expansion ) e)->name == n; + } + + /* Similar to tree_to_aff_combination, but follows SSA name definitions + and expands them recursively. CACHE is used to cache the expansions + of the ssa names, to avoid exponential time complexity for cases + like +
+ a1 = a0 + a0; + a2 = a1 + a1; + a3 = a2 + a2; + ... / + + void + tree_to_aff_combination_expand (tree expr, tree type, aff_tree comb, + htab_t *cache) + { + unsigned i; + aff_tree to_add, current, curre; + tree e, def, rhs; + double_int scale; + void **slot; + struct name_expansion exp; + + tree_to_aff_combination (expr, type, comb); + aff_combination_zero (&to_add, type); + for (i = 0; i < comb->n; i++) + { + e = comb->elts[i].val; + if (TREE_CODE (e) != SSA_NAME) + continue; + def = SSA_NAME_DEF_STMT (e); + if (TREE_CODE (def) != GIMPLE_MODIFY_STMT + || GIMPLE_STMT_OPERAND (def, 0) != e) + continue; + + rhs = GIMPLE_STMT_OPERAND (def, 1); + if (TREE_CODE (rhs) != SSA_NAME + && !EXPR_P (rhs) + && !is_gimple_min_invariant (rhs)) + continue; + + / We do not know whether the reference retains its value at the + place where the expansion is used. / + if (REFERENCE_CLASS_P (rhs)) + continue; + + if (!cache) + cache = htab_create (10, name_expansion_hash, name_expansion_eq, + free); + slot = htab_find_slot_with_hash (cache, e, SSA_NAME_VERSION (e), INSERT); + exp = slot; + + if (exp) + { + / Since we follow the definitions in the SSA form, we should not + enter a cycle unless we pass through a phi node. / + gcc_assert (!exp->in_progress); + current = exp->expansion; + } + else + { + exp = XNEW (struct name_expansion); + exp->name = e; + exp->in_progress = 1; + slot = exp; + tree_to_aff_combination_expand (rhs, type, &current, cache); + exp->expansion = current; + exp->in_progress = 0; + } + + /* Accumulate the new terms to TO_ADD, so that we do not modify + COMB while traversing it; include the term -coef * E, to remove + it from COMB. / + scale = comb->elts[i].coef; + aff_combination_zero (&curre, type); + aff_combination_add_elt (&curre, e, double_int_neg (scale)); + aff_combination_scale (&current, scale); + aff_combination_add (&to_add, &current); + aff_combination_add (&to_add, &curre); + } + aff_combination_add (comb, &to_add); + } + + / If VAL != CST * DIV for any constant CST, returns false. + Otherwise, if VAL != 0 (and hence CST != 0), and MULT_SET is true, + additionally compares CST and MULT, and if they are different, + returns false. Finally, if neither of these two cases occcur, + true is returned, and if CST != 0, CST is stored to MULT and + MULT_SET is set to true. / + + static bool + double_int_constant_multiple_p (double_int val, double_int div, + bool mult_set, double_int mult) + { + double_int rem, cst; + + if (double_int_zero_p (val)) + return true; + + if (double_int_zero_p (div)) + return false; + + cst = double_int_sdivmod (val, div, FLOOR_DIV_EXPR, &rem); + if (!double_int_zero_p (rem)) + return false; + + if (mult_set && !double_int_equal_p (mult, cst)) + return false; + + mult_set = true; + mult = cst; + return true; + } + + /* Returns true if VAL = X * DIV for some constant X. If this is the case, + X is stored to MULT. / + + bool + aff_combination_constant_multiple_p (aff_tree val, aff_tree div, + double_int mult) + { + bool mult_set = false; + unsigned i; + + if (val->n == 0 && double_int_zero_p (val->offset)) + { + mult = double_int_zero; + return true; + } + if (val->n != div->n) + return false; + + if (val->rest || div->rest) + return false; + + if (!double_int_constant_multiple_p (val->offset, div->offset, + &mult_set, mult)) + return false; + + for (i = 0; i < div->n; i++) + { + struct aff_comb_elt elt + = aff_combination_find_elt (val, div->elts[i].val, NULL); + if (!elt) + return false; + if (!double_int_constant_multiple_p (elt->coef, div->elts[i].coef, + &mult_set, mult)) + return false; + } + + gcc_assert (mult_set); + return true; + } Index: tree-affine.h

* tree-affine.h (revision 121952) --- tree-affine.h (working copy) ************* void aff_combination_convert (aff_tree * * 70,72 ** --- 70,74 ---- void tree_to_aff_combination (tree, tree, aff_tree ); tree aff_combination_to_tree (aff_tree ); void unshare_aff_combination (aff_tree ); + bool aff_combination_constant_multiple_p (aff_tree , aff_tree , double_int ); + void tree_to_aff_combination_expand (tree, tree, aff_tree , htab_t ); Index: tree-predcom.c

* tree-predcom.c (revision 0) --- tree-predcom.c (revision 0) *********** * 0 **** --- 1,2602 ---- + /* Predictive commoning. + Copyright (C) 2005 Free Software Foundation, Inc. +
+ This file is part of GCC. +
+ GCC is free software; you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by the + Free Software Foundation; either version 2, or (at your option) any + later version. +
+ GCC is distributed in the hope that it will be useful, but WITHOUT + ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License + for more details. +
+ You should have received a copy of the GNU General Public License + along with GCC; see the file COPYING. If not, write to the Free + Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA + 02110-1301, USA. / + + / This file implements the predictive commoning optimization. Predictive + commoning can be viewed as CSE around a loop, and with some improvements, + as generalized strength reduction-- i.e., reusing values computed in + earlier iterations of a loop in the later ones. So far, the pass only + handles the most useful case, that is, reusing values of memory references. + If you think this is all just a special case of PRE, you are sort of right; + however, concentrating on loops is simpler, and makes it possible to + incorporate data dependence analysis to detect the opportunities, perform + loop unrolling to avoid copies together with renaming immediately, + and if needed, we could also take register pressure into account. + + Let us demonstrate what is done on an example: +
+ for (i = 0; i < 100; i++) + { + a[i+2] = a[i] + a[i+1]; + b[10] = b[10] + i; + c[i] = c[99 - i]; + d[i] = d[i + 1]; + } + + 1) We find data references in the loop, and split them to mutually + independent groups (i.e., we find components of a data dependence + graph). We ignore read-read dependences whose distance is not constant. + (TODO -- we could also ignore antidependences). In this example, we + find the following groups: + + a[i]{read}, a[i+1]{read}, a[i+2]{write} + b[10]{read}, b[10]{write} + c[99 - i]{read}, c[i]{write} + d[i + 1]{read}, d[i]{write} + + 2) Inside each of the group, we verify several conditions: + a) all the references must differ in indices only, and the indices + must all have the same step + b) the references must dominate loop latch (and thus, they must be + ordered by dominance relation). + c) the distance of the indices must be a small multiple of the step + We are then able to compute the difference of the references (# of + iterations before they point to the same place as the first of them). + Also, in case there are writes in the loop, we split the groups into + chains whose head is the write whose values are used by the reads in + the same chain. The chains are then processed independently, + making the further transformations simpler. Also, the shorter chains + need the same number of registers, but may require lower unrolling + factor in order to get rid of the copies on the loop latch. +
+ In our example, we get the following chains (the chain for c is invalid). + + a[i]{read,+0}, a[i+1]{read,-1}, a[i+2]{write,-2} + b[10]{read,+0}, b[10]{write,+0} + d[i + 1]{read,+0}, d[i]{write,+1} + + 3) For each read, we determine the read or write whose value it reuses, + together with the distance of this reuse. I.e. we take the last + reference before it with distance 0, or the last of the references + with the smallest positive distance to the read. Then, we remove + the references that are not used in any of these chains, discard the + empty groups, and propagate all the links so that they point to the + single root reference of the chain (adjusting their distance + appropriately). Some extra care needs to be taken for references with + step 0. In our example (the numbers indicate the distance of the + reuse), + + a[i] --> () 2, a[i+1] --> () 1, a[i+2] () + b[10] --> () 1, b[10] () + + 4) The chains are combined together if possible. If the corresponding + elements of two chains are always combined together with the same + operator, we remember just the result of this combination, instead + of remembering the values separately. We may need to perform + reassociation to enable combining, for example + + e[i] + f[i+1] + e[i+1] + f[i] + + can be reassociated as + + (e[i] + f[i]) + (e[i+1] + f[i+1]) + + and we can combine the chains for e and f into one chain. + + 5) For each root reference (end of the chain) R, let N be maximum distance + of a reference reusing its value. Variables R0 upto RN are created, + together with phi nodes that transfer values from R1 .. RN to + R0 .. R(N-1). + Initial values are loaded to R0..R(N-1) (in case not all references + must necessarily be accessed and they may trap, we may fail here; + TODO sometimes, the loads could be guarded by a check for the number + of iterations). Values loaded/stored in roots are also copied to + RN. Other reads are replaced with the appropriate variable Ri. + Everything is put to SSA form. + + As a small improvement, if R0 is dead after the root (i.e., all uses of + the value with the maximum distance dominate the root), we can avoid + creating RN and use R0 instead of it. + + In our example, we get (only the parts concerning a and b are shown): + for (i = 0; i < 100; i++) + { + f = phi (a[0], s); + s = phi (a[1], f); + x = phi (b[10], x); + + f = f + s; + a[i+2] = f; + x = x + i; + b[10] = x; + } + + 6) Factor F for unrolling is determined as the smallest common multiple of + (N + 1) for each root reference (N for references for that we avoided + creating RN). If F and the loop is small enough, loop is unrolled F + times. The stores to RN (R0) in the copies of the loop body are + periodically replaced with R0, R1, ... (R1, R2, ...), so that they can + be coalesced and the copies can be eliminated. +
+ TODO -- copy propagation and other optimizations may change the life + ranges of the temporary registers and prevent them from being coalesced; + this may increase the register pressure. + + In our case, F = 2 and the (main loop of the) result is + + for (i = 0; i < ...; i += 2) + { + f = phi (a[0], f); + s = phi (a[1], s); + x = phi (b[10], x); + + f = f + s; + a[i+2] = f; + x = x + i; + b[10] = x; + + s = s + f; + a[i+3] = s; + x = x + i; + b[10] = x; + } + + TODO -- stores killing other stores can be taken into account, e.g., + for (i = 0; i < n; i++) + { + a[i] = 1; + a[i+2] = 2; + } + + can be replaced with + + t0 = a[0]; + t1 = a[1]; + for (i = 0; i < n; i++) + { + a[i] = 1; + t2 = 2; + t0 = t1; + t1 = t2; + } + a[n] = t0; + a[n+1] = t1; + + The interesting part is that this would generalize store motion; still, since + sm is performed elsewhere, it does not seem that important. + + Predictive commoning can be generalized for arbitrary computations (not + just memory loads), and also nontrivial transfer functions (e.g., replacing + i * i with ii_last + 2 * i + 1), to generalize strength reduction. / + + #include "config.h" + #include "system.h" + #include "coretypes.h" + #include "tm.h" + #include "tree.h" + #include "tm_p.h" + #include "cfgloop.h" + #include "tree-flow.h" + #include "ggc.h" + #include "tree-data-ref.h" + #include "tree-scalar-evolution.h" + #include "tree-chrec.h" + #include "params.h" + #include "diagnostic.h" + #include "tree-pass.h" + #include "tree-affine.h" + #include "tree-inline.h" + + / The maximum number of iterations between the considered memory + references. / + + #define MAX_DISTANCE (target_avail_regs < 16 ? 4 : 8) +
+ / Data references. / + + typedef struct dref + { + / The reference itself. / + struct data_reference ref; + + /* The statement in that the reference appears. / + tree stmt; + + / Distance of the reference from the root of the chain (in number of + iterations of the loop). / + unsigned distance; + + / Number of iterations offset from the first reference in the component. / + double_int offset; + + / Number of the reference in a component, in dominance ordering. / + unsigned pos; + + / True if the memory reference is always accessed when the loop is + entered. / + unsigned always_accessed : 1; + } dref; + + DEF_VEC_P (dref); + DEF_VEC_ALLOC_P (dref, heap); + + /* Type of the chain of the references. / + + enum chain_type + { + / The addresses of the references in the chain are constant. / + CT_INVARIANT, + + / There are only loads in the chain. / + CT_LOAD, + + / Root of the chain is store, the rest are loads. / + CT_STORE_LOAD, + + / A combination of two chains. / + CT_COMBINATION + }; + + / Chains of data references. / + + typedef struct chain + { + / Type of the chain. / + enum chain_type type; + + / For combination chains, the operator and the two chains that are + combined, and the type of the result. / + enum tree_code operator; + tree rslt_type; + struct chain ch1, ch2; + + / The references in the chain. / + VEC(dref,heap) refs; + + /* The maximum distance of the reference in the chain from the root. / + unsigned length; + + / The variables used to copy the value throughout iterations. / + VEC(tree,heap) vars; + + /* Initializers for the variables. / + VEC(tree,heap) inits; + + /* True if there is a use of a variable with the maximal distance + that comes after the root in the loop. / + unsigned has_max_use_after : 1; + + / True if all the memory references in the chain are always accessed. / + unsigned all_always_accessed : 1; + + / True if this chain was combined together with some other chain. / + unsigned combined : 1; + } chain_p; + + DEF_VEC_P (chain_p); + DEF_VEC_ALLOC_P (chain_p, heap); + + /* Describes the knowledge about the step of the memory references in + the component. / + + enum ref_step_type + { + / The step is zero. / + RS_INVARIANT, + + / The step is nonzero. / + RS_NONZERO, + + / The step may or may not be nonzero. / + RS_ANY + }; + + / Components of the data dependence graph. / + + struct component + { + / The references in the component. / + VEC(dref,heap) refs; + + /* What we know about the step of the references in the component. / + enum ref_step_type comp_step; + + / Next component in the list. / + struct component next; + }; + + /* Bitmap of ssa names defined by looparound phi nodes covered by chains. / + + static bitmap looparound_phis; + + / Cache used by tree_to_aff_combination_expand. / + + static htab_t name_expansions; + + / Dumps data reference REF to FILE. / + + extern void dump_dref (FILE , dref); + void + dump_dref (FILE file, dref ref) + { + if (ref->ref) + { + fprintf (file, " "); + print_generic_expr (file, DR_REF (ref->ref), TDF_SLIM); + fprintf (file, " (id %u%s)\n", ref->pos, + DR_IS_READ (ref->ref) ? "" : ", write"); + + fprintf (file, " offset "); + dump_double_int (file, ref->offset, false); + fprintf (file, "\n"); + + fprintf (file, " distance %u\n", ref->distance); + } + else + { + if (TREE_CODE (ref->stmt) == PHI_NODE) + fprintf (file, " looparound ref\n"); + else + fprintf (file, " combination ref\n"); + fprintf (file, " in statement "); + print_generic_expr (file, ref->stmt, TDF_SLIM); + fprintf (file, "\n"); + fprintf (file, " distance %u\n", ref->distance); + } + + } + + / Dumps CHAIN to FILE. / + + extern void dump_chain (FILE , chain_p); + void + dump_chain (FILE file, chain_p chain) + { + dref a; + const char chain_type; + unsigned i; + tree var; + + switch (chain->type) + { + case CT_INVARIANT: + chain_type = "Load motion"; + break; + + case CT_LOAD: + chain_type = "Loads-only"; + break; + + case CT_STORE_LOAD: + chain_type = "Store-loads"; + break; + + case CT_COMBINATION: + chain_type = "Combination"; + break; + + default: + gcc_unreachable (); + } + + fprintf (file, "%s chain %p%s\n", chain_type, (void ) chain, + chain->combined ? " (combined)" : ""); + if (chain->type != CT_INVARIANT) + fprintf (file, " max distance %u%s\n", chain->length, + chain->has_max_use_after ? "" : ", may reuse first"); + + if (chain->type == CT_COMBINATION) + { + fprintf (file, " equal to %p %s %p in type ", + (void ) chain->ch1, op_symbol_code (chain->operator), + (void ) chain->ch2); + print_generic_expr (file, chain->rslt_type, TDF_SLIM); + fprintf (file, "\n"); + } + + if (chain->vars) + { + fprintf (file, " vars"); + for (i = 0; VEC_iterate (tree, chain->vars, i, var); i++) + { + fprintf (file, " "); + print_generic_expr (file, var, TDF_SLIM); + } + fprintf (file, "\n"); + } + + if (chain->inits) + { + fprintf (file, " inits"); + for (i = 0; VEC_iterate (tree, chain->inits, i, var); i++) + { + fprintf (file, " "); + print_generic_expr (file, var, TDF_SLIM); + } + fprintf (file, "\n"); + } + + fprintf (file, " references:\n"); + for (i = 0; VEC_iterate (dref, chain->refs, i, a); i++) + dump_dref (file, a); + + fprintf (file, "\n"); + } + + / Dumps CHAINS to FILE. / + + extern void dump_chains (FILE , VEC (chain_p, heap) ); + void + dump_chains (FILE file, VEC (chain_p, heap) chains) + { + chain_p chain; + unsigned i; + + for (i = 0; VEC_iterate (chain_p, chains, i, chain); i++) + dump_chain (file, chain); + } + + /* Dumps COMP to FILE. / + + extern void dump_component (FILE , struct component ); + void + dump_component (FILE file, struct component comp) + { + dref a; + unsigned i; + + fprintf (file, "Component%s:\n", + comp->comp_step == RS_INVARIANT ? " (invariant)" : ""); + for (i = 0; VEC_iterate (dref, comp->refs, i, a); i++) + dump_dref (file, a); + fprintf (file, "\n"); + } + + / Dumps COMPS to FILE. / + + extern void dump_components (FILE , struct component ); + void + dump_components (FILE file, struct component comps) + { + struct component comp; + + for (comp = comps; comp; comp = comp->next) + dump_component (file, comp); + } + + /* Frees a chain CHAIN. / + + static void + release_chain (chain_p chain) + { + dref ref; + unsigned i; + + if (chain == NULL) + return; + + for (i = 0; VEC_iterate (dref, chain->refs, i, ref); i++) + free (ref); + + VEC_free (dref, heap, chain->refs); + VEC_free (tree, heap, chain->vars); + VEC_free (tree, heap, chain->inits); + + free (chain); + } + + / Frees CHAINS. / + + static void + release_chains (VEC (chain_p, heap) chains) + { + unsigned i; + chain_p chain; + + for (i = 0; VEC_iterate (chain_p, chains, i, chain); i++) + release_chain (chain); + VEC_free (chain_p, heap, chains); + } + + /* Frees a component COMP. / + + static void + release_component (struct component comp) + { + VEC_free (dref, heap, comp->refs); + free (comp); + } + + /* Frees list of components COMPS. / + + static void + release_components (struct component comps) + { + struct component act, next; + + for (act = comps; act; act = next) + { + next = act->next; + release_component (act); + } + } + + /* Finds a root of tree given by FATHERS containing A, and performs path + shortening. / + + static unsigned + component_of (unsigned fathers[], unsigned a) + { + unsigned root, n; + + for (root = a; root != fathers[root]; root = fathers[root]) + continue; + + for (; a != root; a = n) + { + n = fathers[a]; + fathers[a] = root; + } + + return root; + } + + / Join operation for DFU. FATHERS gives the tree, SIZES are sizes of the + components, A and B are components to merge. / + + static void + merge_comps (unsigned fathers[], unsigned sizes[], unsigned a, unsigned b) + { + unsigned ca = component_of (fathers, a); + unsigned cb = component_of (fathers, b); + + if (ca == cb) + return; + + if (sizes[ca] < sizes[cb]) + { + sizes[cb] += sizes[ca]; + fathers[ca] = cb; + } + else + { + sizes[ca] += sizes[cb]; + fathers[cb] = ca; + } + } + + / Similar to operand_equal_p, but handles the case that X and Y are NULL. / + + static bool + operand_eq_p (tree x, tree y) + { + if (!x) + return y == NULL_TREE; + if (!y) + return false; + + return operand_equal_p (x, y, 0); + } + + / The recursive part of suitable_reference_p. Returns true if A is a reference + that is suitable for predictive commoning in LOOP. REF_STEP is set according to + the step of the reference A. / + + static bool + suitable_reference_p_1 (struct loop loop, tree a, enum ref_step_type ref_step) + { + enum tree_code code; + affine_iv iv; + enum ref_step_type sub_step = RS_INVARIANT; + + if (handled_component_p (a)) + { + code = TREE_CODE (a); + if (!suitable_reference_p_1 (loop, TREE_OPERAND (a, 0), &sub_step)) + return false; + + / To be able to move the initialization of the reference from + the loop, the fields that we do not update must be invariant. / + if (TREE_CODE (a) == COMPONENT_REF + && !expr_invariant_in_loop_p (loop, component_ref_field_offset (a))) + return false; + if (TREE_CODE (a) == ARRAY_REF + && (!expr_invariant_in_loop_p (loop, array_ref_element_size (a)) + || !expr_invariant_in_loop_p (loop, array_ref_low_bound (a)))) + return false; + + if (code != ARRAY_REF) + { + ref_step = sub_step; + return true; + } + + a = TREE_OPERAND (a, 1); + } + else if (DECL_P (a)) + return true; + else if (TREE_CODE (a) == INDIRECT_REF) + a = TREE_OPERAND (a, 0); + else + return false; + + if (!simple_iv (loop, first_stmt (loop->header), a, &iv, true)) + return false; + + if (integer_zerop (iv.step)) + ref_step = sub_step; + else if (integer_nonzerop (iv.step)) + ref_step = RS_NONZERO; + else + ref_step = RS_ANY; + + return true; + } + + / Returns true if A is a reference that is suitable for predictive commoning + in LOOP. REF_STEP is set according to the step of the reference A. / + + static bool + suitable_reference_p (struct loop loop, tree a, enum ref_step_type ref_step) + { + if (!is_gimple_reg_type (TREE_TYPE (a))) + return false; + + return suitable_reference_p_1 (loop, a, ref_step); + } + + / Verifies that A and B are references that look the same way, and splits each + of them to the base part (BASEA, BASEB) and indices (IDXA, IDXB). / + + static bool + split_references (tree a, tree b, + tree basea, tree baseb, tree idxa, tree idxb) + { + enum tree_code code; + + basea = NULL_TREE; + baseb = NULL_TREE; + idxa = NULL_TREE; + idxb = NULL_TREE; + + if (TREE_TYPE (a) != TREE_TYPE (b)) + return false; + + if (handled_component_p (a)) + { + code = TREE_CODE (a); + if (code != TREE_CODE (b)) + return false; + + basea = TREE_OPERAND (a, 0); + baseb = TREE_OPERAND (b, 0); + switch (code) + { + case ARRAY_RANGE_REF: + if (!operand_eq_p (TREE_OPERAND (a, 3), TREE_OPERAND (b, 3))) + return false; + + / Fallthru. / + + case BIT_FIELD_REF: + case COMPONENT_REF: + if (!operand_eq_p (TREE_OPERAND (a, 2), TREE_OPERAND (b, 2))) + return false; + if (!operand_eq_p (TREE_OPERAND (a, 1), TREE_OPERAND (b, 1))) + return false; + + / Fallthru. / + + case VIEW_CONVERT_EXPR: + case REALPART_EXPR: + case IMAGPART_EXPR: + return true; + + case ARRAY_REF: + if (!operand_eq_p (TREE_OPERAND (a, 3), TREE_OPERAND (b, 3))) + return false; + if (!operand_eq_p (TREE_OPERAND (a, 2), TREE_OPERAND (b, 2))) + return false; + + idxa = TREE_OPERAND (a, 1); + idxb = TREE_OPERAND (b, 1); + return true; + + default: + gcc_unreachable (); + } + } + else if (DECL_P (a)) + return operand_equal_p (a, b, 0); + else if (TREE_CODE (a) == INDIRECT_REF && TREE_CODE (b) == INDIRECT_REF) + { + idxa = TREE_OPERAND (a, 0); + idxb = TREE_OPERAND (b, 0); + return true; + } + else + return false; + } + + / Determines number of iterations of LOOP before B refers to exactly the + same location as A and stores it to OFF. If A and B do not have the same + step, they never meet, or anything else fails, returns false, otherwise + returns true. Both A and B are assumed to satisfy suitable_reference_p. / + + static bool + determine_offset (struct loop loop, tree a, tree b, double_int off) + { + affine_iv iva, ivb; + tree type; + aff_tree diff, baseb, step; + double_int aoff; + bool ok; + tree bsa, bsb, idxa, idxb; + + off = double_int_zero; + + if (!split_references (a, b, &bsa, &bsb, &idxa, &idxb)) + return false; + + if (bsa && !determine_offset (loop, bsa, bsb, off)) + return false; + + if (!idxa) + return true; + + / Check whether idxa and idxb are indices with the same step. / + ok = (simple_iv (loop, first_stmt (loop->header), idxa, &iva, true) + && simple_iv (loop, first_stmt (loop->header), idxb, &ivb, true)); + gcc_assert (ok); + + if (!operand_eq_p (iva.step, ivb.step)) + return false; + if (operand_equal_p (iva.base, ivb.base, 0)) + return true; + if (integer_zerop (iva.step)) + return false; + + type = TREE_TYPE (iva.base); + tree_to_aff_combination_expand (iva.base, type, &diff, &name_expansions); + tree_to_aff_combination_expand (ivb.base, type, &baseb, &name_expansions); + aff_combination_scale (&baseb, double_int_minus_one); + aff_combination_add (&diff, &baseb); + + tree_to_aff_combination_expand (iva.step, type, &step, &name_expansions); + if (!aff_combination_constant_multiple_p (&diff, &step, &aoff)) + return false; + + if (!double_int_zero_p (off) && !double_int_equal_p (off, aoff)) + return false; + + off = aoff; + return true; + } + + / Returns the last basic block in LOOP for that we are sure that + it is executed whenever the loop is entered. / + + static basic_block + last_always_executed_block (struct loop loop) + { + unsigned i; + VEC (edge, heap) exits = get_loop_exit_edges (loop); + edge ex; + basic_block last = loop->latch; + + for (i = 0; VEC_iterate (edge, exits, i, ex); i++) + last = nearest_common_dominator (CDI_DOMINATORS, last, ex->src); + VEC_free (edge, heap, exits); + + return last; + } + + / Splits dependence graph on DATAREFS described by DEPENDS to components. / + + static struct component + split_data_refs_to_components (struct loop loop, + VEC (data_reference_p, heap) datarefs, + VEC (ddr_p, heap) depends) + { + unsigned i, n = VEC_length (data_reference_p, datarefs); + unsigned ca, ia, ib, bad; + unsigned comp_father = XNEWVEC (unsigned, n + 1); + unsigned *comp_size = XNEWVEC (unsigned, n + 1); + struct component **comps; + struct data_reference dr, dra, drb; + struct data_dependence_relation ddr; + struct component comp_list = NULL, comp; + dref dataref; + basic_block last_always_executed = last_always_executed_block (loop); +
+ for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++) + { + if (!DR_REF (dr)) + { + / A fake reference for call or asm_expr that may clobber memory; + just fail. / + goto end; + } + dr->aux = i; + comp_father[i] = i; + comp_size[i] = 1; + } + + /* A component reserved for the "bad" data references. / + comp_father[n] = n; + comp_size[n] = 1; + + for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++) + { + enum ref_step_type dummy; + + if (!suitable_reference_p (loop, DR_REF (dr), &dummy)) + { + ia = dr->aux; + merge_comps (comp_father, comp_size, n, ia); + } + } + + for (i = 0; VEC_iterate (ddr_p, depends, i, ddr); i++) + { + double_int dummy_off; + + if (DDR_ARE_DEPENDENT (ddr) == chrec_known) + continue; + + dra = DDR_A (ddr); + drb = DDR_B (ddr); + ia = component_of (comp_father, dra->aux); + ib = component_of (comp_father, drb->aux); + if (ia == ib) + continue; + + bad = component_of (comp_father, n); + + / If both A and B are reads, we may ignore unsuitable dependences. / + if (DR_IS_READ (dra) && DR_IS_READ (drb) + && (ia == bad || ib == bad + || !determine_offset (loop, DR_REF (dra), DR_REF (drb), + &dummy_off))) + continue; +
+ merge_comps (comp_father, comp_size, ia, ib); + } + + comps = XCNEWVEC (struct component , n); + bad = component_of (comp_father, n); + for (i = 0; VEC_iterate (data_reference_p, datarefs, i, dr); i++) + { + ia = dr->aux; + ca = component_of (comp_father, ia); + if (ca == bad) + continue; + + comp = comps[ca]; + if (!comp) + { + comp = XCNEW (struct component); + comp->refs = VEC_alloc (dref, heap, comp_size[ca]); + comps[ca] = comp; + } + + dataref = XCNEW (struct dref); + dataref->ref = dr; + dataref->stmt = DR_STMT (dr); + dataref->offset = double_int_zero; + dataref->distance = 0; + + dataref->always_accessed + = dominated_by_p (CDI_DOMINATORS, last_always_executed, + bb_for_stmt (dataref->stmt)); + dataref->pos = VEC_length (dref, comp->refs); + VEC_quick_push (dref, comp->refs, dataref); + } + + for (i = 0; i < n; i++) + { + comp = comps[i]; + if (comp) + { + comp->next = comp_list; + comp_list = comp; + } + } + free (comps); + + end: + free (comp_father); + free (comp_size); + return comp_list; + } + + / Returns true if the component COMP satisfies the conditions + described in 2) at the begining of this file. LOOP is the current + loop. / +
+ static bool + suitable_component_p (struct loop loop, struct component comp) + { + unsigned i; + dref a; + basic_block ba, bp = loop->header; + tree ref; + bool ok, has_write = false; + + for (i = 0; VEC_iterate (dref, comp->refs, i, a); i++) + { + ba = bb_for_stmt (a->stmt); + + if (!just_once_each_iteration_p (loop, ba)) + return false; + + gcc_assert (dominated_by_p (CDI_DOMINATORS, ba, bp)); + bp = ba; + + if (!DR_IS_READ (a->ref)) + has_write = true; + } + + a = VEC_index (dref, comp->refs, 0); + ref = DR_REF (a->ref); + ok = suitable_reference_p (loop, ref, &comp->comp_step); + gcc_assert (ok); + a->offset = double_int_zero; + + for (i = 1; VEC_iterate (dref, comp->refs, i, a); i++) + { + if (!determine_offset (loop, ref, DR_REF (a->ref), &a->offset)) + return false; + + #ifdef ENABLE_CHECKING + { + enum ref_step_type a_step; + ok = suitable_reference_p (loop, ref, &a_step); + gcc_assert (ok && a_step == comp->comp_step); + } + #endif + } + + / If there is a write inside the component, we must know whether the + step is nonzero or not -- we would not otherwise be able to recognize + whether the value accessed by reads comes from the OFFSET-th iteration + or the previous one. / + if (has_write && comp->comp_step == RS_ANY) + return false; + + return true; + } +
+ / Check the conditions on references inside each of components COMPS, + and remove the unsuitable components from the list. The new list + of components is returned. The conditions are described in 2) at + the begining of this file. LOOP is the current loop. / + + static struct component * + filter_suitable_components (struct loop loop, struct component comps) + { + struct component **comp, act; + + for (comp = &comps; comp; ) + { + act = comp; + if (suitable_component_p (loop, act)) + comp = &act->next; + else + { + comp = act->next; + release_component (act); + } + } + + return comps; + } + + /* Compares two drefs A and B by their offset and position. Callback for + qsort. / + + static int + order_drefs (const void a, const void b) + { + const dref da = a; + const dref db = b; + int offcmp = double_int_scmp ((da)->offset, (db)->offset); + + if (offcmp != 0) + return offcmp; + + return (da)->pos - (db)->pos; + } + + / Returns root of the CHAIN. / + + static inline dref + get_chain_root (chain_p chain) + { + return VEC_index (dref, chain->refs, 0); + } + + / Adds REF to the chain CHAIN. / + + static void + add_ref_to_chain (chain_p chain, dref ref) + { + dref root = get_chain_root (chain); + double_int dist; + + gcc_assert (double_int_scmp (root->offset, ref->offset) <= 0); + dist = double_int_add (ref->offset, double_int_neg (root->offset)); + if (double_int_ucmp (uhwi_to_double_int (MAX_DISTANCE), dist) <= 0) + return; + gcc_assert (double_int_fits_in_uhwi_p (dist)); + + VEC_safe_push (dref, heap, chain->refs, ref); + + ref->distance = double_int_to_uhwi (dist); + + if (ref->distance >= chain->length) + { + chain->length = ref->distance; + chain->has_max_use_after = false; + } + + if (ref->distance == chain->length + && ref->pos > root->pos) + chain->has_max_use_after = true; + + chain->all_always_accessed &= ref->always_accessed; + } + + / Returns the chain for invariant component COMP. / + + static chain_p + make_invariant_chain (struct component comp) + { + chain_p chain = XCNEW (struct chain); + unsigned i; + dref ref; + + chain->type = CT_INVARIANT; + + chain->all_always_accessed = true; + + for (i = 0; VEC_iterate (dref, comp->refs, i, ref); i++) + { + VEC_safe_push (dref, heap, chain->refs, ref); + chain->all_always_accessed &= ref->always_accessed; + } + + return chain; + } + + / Make a new chain rooted at REF. / + + static chain_p + make_rooted_chain (dref ref) + { + chain_p chain = XCNEW (struct chain); + + chain->type = DR_IS_READ (ref->ref) ? CT_LOAD : CT_STORE_LOAD; + + VEC_safe_push (dref, heap, chain->refs, ref); + chain->all_always_accessed = ref->always_accessed; + + ref->distance = 0; + + return chain; + } + + / Returns true if CHAIN is not trivial. / + + static bool + nontrivial_chain_p (chain_p chain) + { + return chain != NULL && VEC_length (dref, chain->refs) > 1; + } + + /* Returns the ssa name that contains the value of REF, or NULL_TREE if there + is no such name. / + + static tree + name_for_ref (dref ref) + { + tree name; + + if (TREE_CODE (ref->stmt) == GIMPLE_MODIFY_STMT) + { + if (!ref->ref || DR_IS_READ (ref->ref)) + name = GIMPLE_STMT_OPERAND (ref->stmt, 0); + else + name = GIMPLE_STMT_OPERAND (ref->stmt, 1); + } + else + name = PHI_RESULT (ref->stmt); + + return (TREE_CODE (name) == SSA_NAME ? name : NULL_TREE); + } + + / Returns true if REF is a valid initializer for ROOT with given DISTANCE (in + iterations of LOOP). / + + static bool + valid_initializer_p (struct loop loop, tree ref, unsigned distance, tree root) + { + tree idx, idxr; + tree bs, bsr, type; + bool ok; + affine_iv ivr; + aff_tree diff, base, step; + double_int off; + + if (!split_references (ref, root, &bs, &bsr, &idx, &idxr)) + return false; + + if (bs && !valid_initializer_p (loop, bs, distance, bsr)) + return false; + + if (!idx) + return true; + + ok = simple_iv (loop, first_stmt (loop->header), idxr, &ivr, true); + gcc_assert (ok); + + if (integer_zerop (ivr.step)) + return operand_equal_p (ivr.base, idx, 0); + + / Verify that this index of REF is equal to the root's index at + -DISTANCE-th iteration. / + type = TREE_TYPE (ivr.base); + tree_to_aff_combination_expand (ivr.base, type, &diff, &name_expansions); + tree_to_aff_combination_expand (idx, type, &base, &name_expansions); + aff_combination_scale (&base, double_int_minus_one); + aff_combination_add (&diff, &base); + + tree_to_aff_combination_expand (ivr.step, type, &step, &name_expansions); + if (!aff_combination_constant_multiple_p (&diff, &step, &off)) + return false; + + if (!double_int_equal_p (off, uhwi_to_double_int (distance))) + return false; + + return true; + } + + / Finds looparound phi node of LOOP that copies the value of REF, and if its + initial value is correct (equal to initial value of REF shifted by one + iteration), returns the phi node. Otherwise, NULL_TREE is returned. ROOT + is the root of the current chain. / + + static tree + find_looparound_phi (struct loop loop, dref ref, dref root) + { + tree name, phi, init, init_stmt, init_ref; + edge latch = loop_latch_edge (loop); + + if (TREE_CODE (ref->stmt) == GIMPLE_MODIFY_STMT) + { + if (DR_IS_READ (ref->ref)) + name = GIMPLE_STMT_OPERAND (ref->stmt, 0); + else + name = GIMPLE_STMT_OPERAND (ref->stmt, 1); + } + else + name = PHI_RESULT (ref->stmt); + if (!name) + return NULL_TREE; + + for (phi = phi_nodes (loop->header); phi; phi = PHI_CHAIN (phi)) + if (PHI_ARG_DEF_FROM_EDGE (phi, latch) == name) + break; + + if (!phi) + return NULL_TREE; + + init = PHI_ARG_DEF_FROM_EDGE (phi, loop_preheader_edge (loop)); + if (TREE_CODE (init) != SSA_NAME) + return NULL_TREE; + init_stmt = SSA_NAME_DEF_STMT (init); + if (TREE_CODE (init_stmt) != GIMPLE_MODIFY_STMT) + return NULL_TREE; + gcc_assert (GIMPLE_STMT_OPERAND (init_stmt, 0) == init); + + init_ref = GIMPLE_STMT_OPERAND (init_stmt, 1); + if (!valid_initializer_p (loop, init_ref, ref->distance + 1, DR_REF (root->ref))) + return NULL_TREE; + + return phi; + } + + / Adds a reference for the looparound copy of REF in PHI to CHAIN. / + + static void + insert_looparound_copy (chain_p chain, dref ref, tree phi) + { + dref nw = XCNEW (struct dref), aref; + unsigned i; + + nw->stmt = phi; + nw->distance = ref->distance + 1; + nw->always_accessed = 1; + + for (i = 0; VEC_iterate (dref, chain->refs, i, aref); i++) + if (aref->distance >= nw->distance) + break; + VEC_safe_insert (dref, heap, chain->refs, i, nw); + + if (nw->distance > chain->length) + { + chain->length = nw->distance; + chain->has_max_use_after = false; + } + } + + / For references in CHAIN that are copied around the LOOP (created previously + by PRE, or by user), add the results of such copies to the chain. This + enables us to remove the copies by unrolling, and may need less registers + (also, it may allow us to combine chains together). / + + static void + add_looparound_copies (struct loop loop, chain_p chain) + { + unsigned i; + dref ref, root = get_chain_root (chain); + tree phi; + + for (i = 0; VEC_iterate (dref, chain->refs, i, ref); i++) + { + phi = find_looparound_phi (loop, ref, root); + if (!phi) + continue; + + bitmap_set_bit (looparound_phis, SSA_NAME_VERSION (PHI_RESULT (phi))); + insert_looparound_copy (chain, ref, phi); + } + } + + / Find roots of the values and determine distances in the component COMP. + The references are redistributed into CHAINS. LOOP is the current + loop. / + + static void + determine_roots_comp (struct loop loop, + struct component comp, + VEC (chain_p, heap) **chains) + { + unsigned i; + dref a; + chain_p chain = NULL; + + /* Invariants are handled specially. / + if (comp->comp_step == RS_INVARIANT) + { + chain = make_invariant_chain (comp); + VEC_safe_push (chain_p, heap, chains, chain); + return; + } + + qsort (VEC_address (dref, comp->refs), VEC_length (dref, comp->refs), + sizeof (dref), order_drefs); + + for (i = 0; VEC_iterate (dref, comp->refs, i, a); i++) + { + if (!chain || !DR_IS_READ (a->ref)) + { + if (nontrivial_chain_p (chain)) + VEC_safe_push (chain_p, heap, chains, chain); + else + release_chain (chain); + chain = make_rooted_chain (a); + continue; + } + + add_ref_to_chain (chain, a); + } + + if (nontrivial_chain_p (chain)) + { + add_looparound_copies (loop, chain); + VEC_safe_push (chain_p, heap, chains, chain); + } + else + release_chain (chain); + } + + /* Find roots of the values and determine distances in components COMPS, and + separates the references to CHAINS. LOOP is the current loop. / + + static void + determine_roots (struct loop loop, + struct component *comps, VEC (chain_p, heap) **chains) + { + struct component comp; + + for (comp = comps; comp; comp = comp->next) + determine_roots_comp (loop, comp, chains); + } + + / Replace the reference in statement STMT with temporary variable + NEW. If SET is true, NEW is instead initialized to the value of + the reference in the statement. IN_LHS is true if the reference + is in the lhs of STMT, false if it is in rhs. / + + static void + replace_ref_with (tree stmt, tree new, bool set, bool in_lhs) + { + tree val, new_stmt; + block_stmt_iterator bsi; + + if (TREE_CODE (stmt) == PHI_NODE) + { + gcc_assert (!in_lhs && !set); + + val = PHI_RESULT (stmt); + bsi = bsi_after_labels (bb_for_stmt (stmt)); + remove_phi_node (stmt, NULL_TREE, false); + + / Turn the phi node into GIMPLE_MODIFY_STMT. / + new_stmt = build2_gimple (GIMPLE_MODIFY_STMT, val, new); + SSA_NAME_DEF_STMT (val) = new_stmt; + bsi_insert_before (&bsi, new_stmt, BSI_NEW_STMT); + return; + } +
+ / Since the reference is of gimple_reg type, it should only + appear as lhs or rhs of modify statement. / + gcc_assert (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT); + + / If we do not need to initialize NEW, just replace the use of OLD. / + if (!set) + { + gcc_assert (!in_lhs); + GIMPLE_STMT_OPERAND (stmt, 1) = new; + update_stmt (stmt); + return; + } + + bsi = bsi_for_stmt (stmt); + if (in_lhs) + { + val = GIMPLE_STMT_OPERAND (stmt, 1); + + / OLD = VAL + + is transformed to + + OLD = VAL + NEW = VAL + + (since the reference is of gimple_reg type, VAL is either gimple + invariant or ssa name). / + } + else + { + val = GIMPLE_STMT_OPERAND (stmt, 0); + + / VAL = OLD + + is transformed to + + VAL = OLD + NEW = VAL / + } + + new_stmt = build2_gimple (GIMPLE_MODIFY_STMT, new, unshare_expr (val)); + bsi_insert_after (&bsi, new_stmt, BSI_NEW_STMT); + SSA_NAME_DEF_STMT (new) = new_stmt; + } + + / Specializes REF for the ITER-th iteration (ITER may be negative). / + + static void + ref_at_iteration (struct loop loop, tree ref, int iter) + { + tree idx, type, val; + affine_iv iv; + bool ok; + + if (handled_component_p (ref)) + ref_at_iteration (loop, TREE_OPERAND (ref, 0), iter); + + if (TREE_CODE (ref) == ARRAY_REF) + idx = &TREE_OPERAND (ref, 1); + else if (TREE_CODE (ref) == INDIRECT_REF) + idx = &TREE_OPERAND (ref, 0); + else + return; + + ok = simple_iv (loop, first_stmt (loop->header), idx, &iv, true); + iv.base = expand_simple_operations (iv.base); + gcc_assert (ok); + if (integer_zerop (iv.step)) + { + idx = unshare_expr (iv.base); + return; + } + + type = TREE_TYPE (iv.base); + val = fold_build2 (MULT_EXPR, type, iv.step, + build_int_cst_type (type, iter)); + val = fold_build2 (PLUS_EXPR, type, iv.base, val); + idx = unshare_expr (val); + } + + /* Get the initialization expression for the INDEX-th temporary variable + of CHAIN. / + + static tree + get_init_expr (chain_p chain, unsigned index) + { + if (chain->type == CT_COMBINATION) + { + tree e1 = get_init_expr (chain->ch1, index); + tree e2 = get_init_expr (chain->ch2, index); + + return fold_build2 (chain->operator, chain->rslt_type, e1, e2); + } + else + return VEC_index (tree, chain->inits, index); + } + + / Marks all virtual operands of statement STMT for renaming. / + + static void + mark_virtual_ops_for_renaming (tree stmt) + { + ssa_op_iter iter; + tree var; + + if (TREE_CODE (stmt) == PHI_NODE) + return; + + update_stmt (stmt); + + FOR_EACH_SSA_TREE_OPERAND (var, stmt, iter, SSA_OP_ALL_VIRTUALS) + { + if (TREE_CODE (var) == SSA_NAME) + var = SSA_NAME_VAR (var); + mark_sym_for_renaming (var); + } + } + + / Calls mark_virtual_ops_for_renaming for all members of LIST. / + + static void + mark_virtual_ops_for_renaming_list (tree list) + { + tree_stmt_iterator tsi; + + for (tsi = tsi_start (list); !tsi_end_p (tsi); tsi_next (&tsi)) + mark_virtual_ops_for_renaming (tsi_stmt (tsi)); + } + + / Creates the variables for CHAIN, as well as phi nodes for them and + initialization on entry to LOOP. Uids of the newly created + temporary variables are marked in TMP_VARS. / + + static void + initialize_root_vars (struct loop loop, chain_p chain, bitmap tmp_vars) + { + unsigned i; + unsigned n = chain->length; + dref root = get_chain_root (chain); + bool reuse_first = !chain->has_max_use_after; + tree ref, init, var, next, stmts; + tree phi; + edge entry = loop_preheader_edge (loop), latch = loop_latch_edge (loop); + + / If N == 0, then all the references are within the single iteration. And + since this is an nonempty chain, reuse_first cannot be true. / + gcc_assert (n > 0 || !reuse_first); + + chain->vars = VEC_alloc (tree, heap, n + 1); + + if (chain->type == CT_COMBINATION) + ref = GIMPLE_STMT_OPERAND (root->stmt, 0); + else + ref = DR_REF (root->ref); + + for (i = 0; i < n + (reuse_first ? 0 : 1); i++) + { + var = create_tmp_var (TREE_TYPE (ref), get_lsm_tmp_name (ref, i)); + add_referenced_var (var); + bitmap_set_bit (tmp_vars, DECL_UID (var)); + VEC_quick_push (tree, chain->vars, var); + } + if (reuse_first) + VEC_quick_push (tree, chain->vars, VEC_index (tree, chain->vars, 0)); +
+ for (i = 0; VEC_iterate (tree, chain->vars, i, var); i++) + VEC_replace (tree, chain->vars, i, make_ssa_name (var, NULL_TREE)); + + for (i = 0; i < n; i++) + { + var = VEC_index (tree, chain->vars, i); + next = VEC_index (tree, chain->vars, i + 1); + init = get_init_expr (chain, i); + + init = force_gimple_operand (init, &stmts, true, NULL_TREE); + if (stmts) + { + mark_virtual_ops_for_renaming_list (stmts); + bsi_insert_on_edge_immediate (entry, stmts); + } + + phi = create_phi_node (var, loop->header); + SSA_NAME_DEF_STMT (var) = phi; + add_phi_arg (phi, init, entry); + add_phi_arg (phi, next, latch); + } + } + + / Create the variables and initialization statement for root of chain + CHAIN. Uids of the newly created temporary variables are marked + in TMP_VARS. / + + static void + initialize_root (struct loop loop, chain_p chain, bitmap tmp_vars) + { + dref root = get_chain_root (chain); + bool in_lhs = (chain->type == CT_STORE_LOAD + || chain->type == CT_COMBINATION); + + initialize_root_vars (loop, chain, tmp_vars); + replace_ref_with (root->stmt, + VEC_index (tree, chain->vars, chain->length), + true, in_lhs); + } + + / Initializes a variable for load motion for ROOT and prepares phi nodes and + initialization on entry to LOOP if necessary. The ssa name for the variable + is stored in VARS. If WRITTEN is true, also a phi node to copy its value + around the loop is created. Uid of the newly created temporary variable + is marked in TMP_VARS. INITS is the list containing the (single) + initializer. / + + static void + initialize_root_vars_lm (struct loop loop, dref root, bool written, + VEC(tree, heap) **vars, VEC(tree, heap) inits, + bitmap tmp_vars) + { + unsigned i; + tree ref = DR_REF (root->ref), init, var, next, stmts; + tree phi; + edge entry = loop_preheader_edge (loop), latch = loop_latch_edge (loop); + + / Find the initializer for the variable, and check that it cannot + trap. / + init = VEC_index (tree, inits, 0); + + vars = VEC_alloc (tree, heap, written ? 2 : 1); + var = create_tmp_var (TREE_TYPE (ref), get_lsm_tmp_name (ref, 0)); + add_referenced_var (var); + bitmap_set_bit (tmp_vars, DECL_UID (var)); + VEC_quick_push (tree, vars, var); + if (written) + VEC_quick_push (tree, vars, VEC_index (tree, vars, 0)); +
+ for (i = 0; VEC_iterate (tree, vars, i, var); i++) + VEC_replace (tree, vars, i, make_ssa_name (var, NULL_TREE)); + + var = VEC_index (tree, vars, 0); +
+ init = force_gimple_operand (init, &stmts, written, NULL_TREE); + if (stmts) + { + mark_virtual_ops_for_renaming_list (stmts); + bsi_insert_on_edge_immediate (entry, stmts); + } + + if (written) + { + next = VEC_index (tree, vars, 1); + phi = create_phi_node (var, loop->header); + SSA_NAME_DEF_STMT (var) = phi; + add_phi_arg (phi, init, entry); + add_phi_arg (phi, next, latch); + } + else + { + init = build2_gimple (GIMPLE_MODIFY_STMT, var, init); + SSA_NAME_DEF_STMT (var) = init; + mark_virtual_ops_for_renaming (init); + bsi_insert_on_edge_immediate (entry, init); + } + } + + + / Execute load motion for references in chain CHAIN. Uids of the newly + created temporary variables are marked in TMP_VARS. / + + static void + execute_load_motion (struct loop loop, chain_p chain, bitmap tmp_vars) + { + VEC (tree, heap) vars; + dref a; + unsigned n_writes = 0, ridx, i; + tree var; + + gcc_assert (chain->type == CT_INVARIANT); + gcc_assert (!chain->combined); + for (i = 0; VEC_iterate (dref, chain->refs, i, a); i++) + if (!DR_IS_READ (a->ref)) + n_writes++; +
+ / If there are no reads in the loop, there is nothing to do. / + if (n_writes == VEC_length (dref, chain->refs)) + return; + + initialize_root_vars_lm (loop, get_chain_root (chain), n_writes > 0, + &vars, chain->inits, tmp_vars); + + ridx = 0; + for (i = 0; VEC_iterate (dref, chain->refs, i, a); i++) + { + bool is_read = DR_IS_READ (a->ref); + mark_virtual_ops_for_renaming (a->stmt); + + if (!DR_IS_READ (a->ref)) + { + n_writes--; + if (n_writes) + { + var = VEC_index (tree, vars, 0); + var = make_ssa_name (SSA_NAME_VAR (var), NULL_TREE); + VEC_replace (tree, vars, 0, var); + } + else + ridx = 1; + } +
+ replace_ref_with (a->stmt, VEC_index (tree, vars, ridx), + !is_read, !is_read); + } + + VEC_free (tree, heap, vars); + } + + / Returns the single statement in that NAME is used, excepting + the looparound phi nodes contained in one of the chains. If there is no + such statement, or more statements, NULL_TREE is returned. / + + static tree + single_nonlooparound_use (tree name) + { + use_operand_p use; + imm_use_iterator it; + tree stmt, ret = NULL_TREE; + + FOR_EACH_IMM_USE_FAST (use, it, name) + { + stmt = USE_STMT (use); + + if (TREE_CODE (stmt) == PHI_NODE) + { + / Ignore uses in looparound phi nodes. Uses in other phi nodes + could not be processed anyway, so just fail for them. / + if (bitmap_bit_p (looparound_phis, + SSA_NAME_VERSION (PHI_RESULT (stmt)))) + continue; + + return NULL_TREE; + } + else if (ret != NULL_TREE) + return NULL_TREE; + else + ret = stmt; + } + + return ret; + } + + / Remove statement STMT, as well as the chain of assignments in that it is + used. / + + static void + remove_stmt (tree stmt) + { + tree next, name; + + if (TREE_CODE (stmt) == PHI_NODE) + { + name = PHI_RESULT (stmt); + next = single_nonlooparound_use (name); + remove_phi_node (stmt, NULL_TREE, true); + + if (!next + || TREE_CODE (next) != GIMPLE_MODIFY_STMT + || GIMPLE_STMT_OPERAND (next, 1) != name) + return; + + stmt = next; + } + + while (1) + { + block_stmt_iterator bsi; +
+ bsi = bsi_for_stmt (stmt); + + name = GIMPLE_STMT_OPERAND (stmt, 0); + gcc_assert (TREE_CODE (name) == SSA_NAME); + + next = single_nonlooparound_use (name); + + mark_virtual_ops_for_renaming (stmt); + bsi_remove (&bsi, true); + + if (!next + || TREE_CODE (next) != GIMPLE_MODIFY_STMT + || GIMPLE_STMT_OPERAND (next, 1) != name) + return; + + stmt = next; + } + } + + / Perform the predictive commoning optimization for a chain CHAIN. + Uids of the newly created temporary variables are marked in TMP_VARS./ + + static void + execute_pred_commoning_chain (struct loop loop, chain_p chain, + bitmap tmp_vars) + { + unsigned i; + dref a, root; + tree var; + + if (chain->combined) + { + /* For combined chains, just remove the statements that are used to + compute the values of the expression (except for the root one). / + for (i = 1; VEC_iterate (dref, chain->refs, i, a); i++) + remove_stmt (a->stmt); + } + else + { + / For non-combined chains, set up the variables that hold its value, + and replace the uses of the original references by these + variables. / + root = get_chain_root (chain); + mark_virtual_ops_for_renaming (root->stmt); + + initialize_root (loop, chain, tmp_vars); + for (i = 1; VEC_iterate (dref, chain->refs, i, a); i++) + { + mark_virtual_ops_for_renaming (a->stmt); + var = VEC_index (tree, chain->vars, chain->length - a->distance); + replace_ref_with (a->stmt, var, false, false); + } + } + } + + / Determines the unroll factor necessary to remove as many temporary variable + copies as possible. CHAINS is the list of chains that will be + optimized. / + + static unsigned + determine_unroll_factor (VEC (chain_p, heap) chains) + { + chain_p chain; + unsigned factor = 1, af, nfactor, i; + unsigned max = PARAM_VALUE (PARAM_MAX_UNROLL_TIMES); + + for (i = 0; VEC_iterate (chain_p, chains, i, chain); i++) + { + if (chain->type == CT_INVARIANT || chain->combined) + continue; + + / The best unroll factor for this chain is equal to the number of + temporary variables that we create for it. / + af = chain->length; + if (chain->has_max_use_after) + af++; + + nfactor = factor af / gcd (factor, af); + if (nfactor <= max) + factor = nfactor; + } + + return factor; + } + + /* Perform the predictive commoning optimization for CHAINS. + Uids of the newly created temporary variables are marked in TMP_VARS. / + + static void + execute_pred_commoning (struct loop loop, VEC (chain_p, heap) chains, + bitmap tmp_vars) + { + chain_p chain; + unsigned i; + + for (i = 0; VEC_iterate (chain_p, chains, i, chain); i++) + { + if (chain->type == CT_INVARIANT) + execute_load_motion (loop, chain, tmp_vars); + else + execute_pred_commoning_chain (loop, chain, tmp_vars); + } +
+ update_ssa (TODO_update_ssa_only_virtuals); + } + + / Wrapper over execute_pred_commoning, to pass it as a callback + to tree_transform_and_unroll_loop. / + + struct epcc_data + { + VEC (chain_p, heap) chains; + bitmap tmp_vars; + }; + + static void + execute_pred_commoning_cbck (struct loop loop, void data) + { + struct epcc_data dta = data; + + execute_pred_commoning (loop, dta->chains, dta->tmp_vars); + } + + /* Returns true if we can and should unroll LOOP FACTOR times. Number + of iterations of the loop is returned in NITER. / + + static bool + should_unroll_loop_p (struct loop loop, unsigned factor, + struct tree_niter_desc niter) + { + edge exit; + + if (factor == 1) + return false; + + / Check whether unrolling is possible. We only want to unroll loops + for that we are able to determine number of iterations. We also + want to split the extra iterations of the loop from its end, + therefore we require that the loop has precisely one + exit. / + + exit = single_dom_exit (loop); + if (!exit) + return false; + + if (!number_of_iterations_exit (loop, exit, niter, false)) + return false; + + / And of course, we must be able to duplicate the loop. / + if (!can_duplicate_loop_p (loop)) + return false; + + / The final loop should be small enough. / + if (tree_num_loop_insns (loop, &eni_size_weights) factor + > (unsigned) PARAM_VALUE (PARAM_MAX_UNROLLED_INSNS)) + return false; + + return true; + } + + /* Base NAME and all the names in the chain of phi nodes that use it + on variable VAR. The phi nodes are recognized by being in the copies of + the header of the LOOP. / + + static void + base_names_in_chain_on (struct loop loop, tree name, tree var) + { + tree stmt, phi; + imm_use_iterator iter; + edge e; + + SSA_NAME_VAR (name) = var; + + while (1) + { + phi = NULL; + FOR_EACH_IMM_USE_STMT (stmt, iter, name) + { + if (TREE_CODE (stmt) == PHI_NODE + && flow_bb_inside_loop_p (loop, bb_for_stmt (stmt))) + { + phi = stmt; + BREAK_FROM_IMM_USE_STMT (iter); + } + } + if (!phi) + return; + + if (bb_for_stmt (phi) == loop->header) + e = loop_latch_edge (loop); + else + e = single_pred_edge (bb_for_stmt (stmt)); + + name = PHI_RESULT (phi); + SSA_NAME_VAR (name) = var; + } + } + + / Given an unrolled LOOP after predictive commoning, remove the + register copies arising from phi nodes by changing the base + variables of SSA names. TMP_VARS is the set of the temporary variables + for those we want to perform this. / + + static void + eliminate_temp_copies (struct loop loop, bitmap tmp_vars) + { + edge e; + tree phi, name, use, var, stmt; + + e = loop_latch_edge (loop); + for (phi = phi_nodes (loop->header); phi; phi = PHI_CHAIN (phi)) + { + name = PHI_RESULT (phi); + var = SSA_NAME_VAR (name); + if (!bitmap_bit_p (tmp_vars, DECL_UID (var))) + continue; + use = PHI_ARG_DEF_FROM_EDGE (phi, e); + gcc_assert (TREE_CODE (use) == SSA_NAME); + + / Base all the ssa names in the ud and du chain of NAME on VAR. / + stmt = SSA_NAME_DEF_STMT (use); + while (TREE_CODE (stmt) == PHI_NODE) + { + gcc_assert (single_pred_p (bb_for_stmt (stmt))); + use = PHI_ARG_DEF (stmt, 0); + stmt = SSA_NAME_DEF_STMT (use); + } + + base_names_in_chain_on (loop, use, var); + } + } + + / Returns true if CHAIN is suitable to be combined. / + + static bool + chain_can_be_combined_p (chain_p chain) + { + return (!chain->combined + && (chain->type == CT_LOAD || chain->type == CT_COMBINATION)); + } + + / Returns the modify statement that uses NAME. Skips over assignment + statements, NAME is replaced with the actual name used in the returned + statement. / + + static tree + find_use_stmt (tree name) + { + tree stmt, rhs, lhs; + + /* Skip over assignments. / + while (1) + { + stmt = single_nonlooparound_use (name); + if (!stmt) + return NULL_TREE; + + if (TREE_CODE (stmt) != GIMPLE_MODIFY_STMT) + return NULL_TREE; + + lhs = GIMPLE_STMT_OPERAND (stmt, 0); + if (TREE_CODE (lhs) != SSA_NAME) + return NULL_TREE; + + rhs = GIMPLE_STMT_OPERAND (stmt, 1); + if (rhs != name) + break; + + name = lhs; + } + + if (!EXPR_P (rhs) + || REFERENCE_CLASS_P (rhs) + || TREE_CODE_LENGTH (TREE_CODE (rhs)) != 2) + return NULL_TREE; + + return stmt; + } + + /* Returns true if we may perform reassociation for operation CODE in TYPE. / + + static bool + may_reassociate_p (tree type, enum tree_code code) + { + if (FLOAT_TYPE_P (type) + && !flag_unsafe_math_optimizations) + return false; + + return (commutative_tree_code (code) + && associative_tree_code (code)); + } + + / If the operation used in STMT is associative and commutative, go through the + tree of the same operations and returns its root. Distance to the root + is stored in DISTANCE. / + + static tree + find_associative_operation_root (tree stmt, unsigned distance) + { + tree rhs = GIMPLE_STMT_OPERAND (stmt, 1), lhs, next; + enum tree_code code = TREE_CODE (rhs); + unsigned dist = 0; + + if (!may_reassociate_p (TREE_TYPE (rhs), code)) + return NULL_TREE; + + while (1) + { + lhs = GIMPLE_STMT_OPERAND (stmt, 0); + gcc_assert (TREE_CODE (lhs) == SSA_NAME); + + next = find_use_stmt (&lhs); + if (!next) + break; + + rhs = GIMPLE_STMT_OPERAND (next, 1); + if (TREE_CODE (rhs) != code) + break; + + stmt = next; + dist++; + } + + if (distance) + distance = dist; + return stmt; + } + + / Returns the common statement in that NAME1 and NAME2 have a use. If there + is no such statement, returns NULL_TREE. In case the operation used on + NAME1 and NAME2 is associative and comutative, returns the root of the + tree formed by this operation instead of the statement that uses NAME1 or + NAME2. / + + static tree + find_common_use_stmt (tree name1, tree name2) + { + tree stmt1, stmt2; + + stmt1 = find_use_stmt (name1); + if (!stmt1) + return NULL_TREE; + + stmt2 = find_use_stmt (name2); + if (!stmt2) + return NULL_TREE; + + if (stmt1 == stmt2) + return stmt1; + + stmt1 = find_associative_operation_root (stmt1, NULL); + if (!stmt1) + return NULL_TREE; + stmt2 = find_associative_operation_root (stmt2, NULL); + if (!stmt2) + return NULL_TREE; + + return (stmt1 == stmt2 ? stmt1 : NULL_TREE); + } + + / Checks whether R1 and R2 are combined together using CODE, with the result + in RSLT_TYPE, in order R1 CODE R2 if SWAP is false and in order R2 CODE R1 + if it is true. If CODE is ERROR_MARK, set these values instead. / + + static bool + combinable_refs_p (dref r1, dref r2, + enum tree_code code, bool swap, tree rslt_type) + { + enum tree_code acode; + bool aswap; + tree atype; + tree name1, name2, stmt, rhs; + + name1 = name_for_ref (r1); + name2 = name_for_ref (r2); + gcc_assert (name1 != NULL_TREE && name2 != NULL_TREE); + + stmt = find_common_use_stmt (&name1, &name2); + + if (!stmt) + return false; + + rhs = GIMPLE_STMT_OPERAND (stmt, 1); + acode = TREE_CODE (rhs); + aswap = (!commutative_tree_code (acode) + && TREE_OPERAND (rhs, 0) != name1); + atype = TREE_TYPE (rhs); + + if (code == ERROR_MARK) + { + code = acode; + swap = aswap; + rslt_type = atype; + return true; + } + + return (code == acode + && swap == aswap + && rslt_type == atype); + } + + / Remove OP from the operation on rhs of STMT, and replace STMT with + an assignment of the remaining operand. / + + static void + remove_name_from_operation (tree stmt, tree op) + { + tree rhs; + + gcc_assert (TREE_CODE (stmt) == GIMPLE_MODIFY_STMT); + + rhs = &GIMPLE_STMT_OPERAND (stmt, 1); + if (TREE_OPERAND (rhs, 0) == op) + rhs = TREE_OPERAND (rhs, 1); + else if (TREE_OPERAND (rhs, 1) == op) + rhs = TREE_OPERAND (rhs, 0); + else + gcc_unreachable (); + update_stmt (stmt); + } + + /* Reassociates the expression in that NAME1 and NAME2 are used so that they + are combined in a single statement, and returns this statement. / + + static tree + reassociate_to_the_same_stmt (tree name1, tree name2) + { + tree stmt1, stmt2, root1, root2, r1, r2, s1, s2; + tree new_stmt, tmp_stmt, new_name, tmp_name, var; + unsigned dist1, dist2; + enum tree_code code; + tree type = TREE_TYPE (name1); + block_stmt_iterator bsi; + + stmt1 = find_use_stmt (&name1); + stmt2 = find_use_stmt (&name2); + root1 = find_associative_operation_root (stmt1, &dist1); + root2 = find_associative_operation_root (stmt2, &dist2); + code = TREE_CODE (GIMPLE_STMT_OPERAND (stmt1, 1)); + + gcc_assert (root1 && root2 && root1 == root2 + && code == TREE_CODE (GIMPLE_STMT_OPERAND (stmt2, 1))); + + / Find the root of the nearest expression in that both NAME1 and NAME2 + are used. / + r1 = name1; + s1 = stmt1; + r2 = name2; + s2 = stmt2; + + while (dist1 > dist2) + { + s1 = find_use_stmt (&r1); + r1 = GIMPLE_STMT_OPERAND (s1, 0); + dist1--; + } + while (dist2 > dist1) + { + s2 = find_use_stmt (&r2); + r2 = GIMPLE_STMT_OPERAND (s2, 0); + dist2--; + } + + while (s1 != s2) + { + s1 = find_use_stmt (&r1); + r1 = GIMPLE_STMT_OPERAND (s1, 0); + s2 = find_use_stmt (&r2); + r2 = GIMPLE_STMT_OPERAND (s2, 0); + } + + / Remove NAME1 and NAME2 from the statements in that they are used + currently. / + remove_name_from_operation (stmt1, name1); + remove_name_from_operation (stmt2, name2); + + / Insert the new statement combining NAME1 and NAME2 before S1, and + combine it with the rhs of S1. / + var = create_tmp_var (type, "predreastmp"); + add_referenced_var (var); + new_name = make_ssa_name (var, NULL_TREE); + new_stmt = build2_gimple (GIMPLE_MODIFY_STMT, new_name, + fold_build2 (code, type, name1, name2)); + SSA_NAME_DEF_STMT (new_name) = new_stmt; + + var = create_tmp_var (type, "predreastmp"); + add_referenced_var (var); + tmp_name = make_ssa_name (var, NULL_TREE); + tmp_stmt = build2_gimple (GIMPLE_MODIFY_STMT, tmp_name, GIMPLE_STMT_OPERAND (s1, 1)); + SSA_NAME_DEF_STMT (tmp_name) = tmp_stmt; + + GIMPLE_STMT_OPERAND (s1, 1) = fold_build2 (code, type, new_name, tmp_name); + update_stmt (s1); + + bsi = bsi_for_stmt (s1); + bsi_insert_before (&bsi, new_stmt, BSI_SAME_STMT); + bsi_insert_before (&bsi, tmp_stmt, BSI_SAME_STMT); + + return new_stmt; + } + + / Returns the statement that combines references R1 and R2. In case R1 + and R2 are not used in the same statement, but they are used with an + associative and commutative operation in the same expression, reassociate + the expression so that they are used in the same statement. / + + static tree + stmt_combining_refs (dref r1, dref r2) + { + tree stmt1, stmt2; + tree name1 = name_for_ref (r1); + tree name2 = name_for_ref (r2); + + stmt1 = find_use_stmt (&name1); + stmt2 = find_use_stmt (&name2); + if (stmt1 == stmt2) + return stmt1; + + return reassociate_to_the_same_stmt (name1, name2); + } + + / Tries to combine chains CH1 and CH2 together. If this succeeds, the + description of the new chain is returned, otherwise we return NULL. / + + static chain_p + combine_chains (chain_p ch1, chain_p ch2) + { + dref r1, r2, nw; + enum tree_code op = ERROR_MARK; + bool swap = false; + chain_p new_chain; + unsigned i; + tree root_stmt; + tree rslt_type = NULL_TREE; + + if (ch1 == ch2) + return false; + if (ch1->length != ch2->length) + return NULL; + + if (VEC_length (dref, ch1->refs) != VEC_length (dref, ch2->refs)) + return NULL; + + for (i = 0; (VEC_iterate (dref, ch1->refs, i, r1) + && VEC_iterate (dref, ch2->refs, i, r2)); i++) + { + if (r1->distance != r2->distance) + return NULL; + + if (!combinable_refs_p (r1, r2, &op, &swap, &rslt_type)) + return NULL; + } + + if (swap) + { + chain_p tmp = ch1; + ch1 = ch2; + ch2 = tmp; + } + + new_chain = XCNEW (struct chain); + new_chain->type = CT_COMBINATION; + new_chain->operator = op; + new_chain->ch1 = ch1; + new_chain->ch2 = ch2; + new_chain->rslt_type = rslt_type; + new_chain->length = ch1->length; + + for (i = 0; (VEC_iterate (dref, ch1->refs, i, r1) + && VEC_iterate (dref, ch2->refs, i, r2)); i++) + { + nw = XCNEW (struct dref); + nw->stmt = stmt_combining_refs (r1, r2); + nw->distance = r1->distance; + + VEC_safe_push (dref, heap, new_chain->refs, nw); + } + + new_chain->has_max_use_after = false; + root_stmt = get_chain_root (new_chain)->stmt; + for (i = 1; VEC_iterate (dref, new_chain->refs, i, nw); i++) + { + if (nw->distance == new_chain->length + && !stmt_dominates_stmt_p (nw->stmt, root_stmt)) + { + new_chain->has_max_use_after = true; + break; + } + } + + ch1->combined = true; + ch2->combined = true; + return new_chain; + } + + / Try to combine the CHAINS. */ + + static void + try_combine_chains (VEC (chain_p, heap) **chains) + { + unsigned i, j; + chain_p ch1, ch2, cch; + VEC (chain_p, heap) worklist = NULL; + + for (i = 0; VEC_iterate (chain_p, chains, i, ch1); i++) + if (chain_can_be_combined_p (ch1)) + VEC_safe_push (chain_p, heap, worklist, ch1); + + while (!VEC_empty (chain_p, worklist)) + { + ch1 = VEC_pop (chain_p, worklist); + if (!chain_can_be_combined_p (ch1)) + continue; + + for (j = 0; VEC_iterate (chain_p, chains, j, ch2); j++) + { + if (!chain_can_be_combined_p (ch2)) + continue; + + cch = combine_chains (ch1, ch2); + if (cch) + { + VEC_safe_push (chain_p, heap, worklist, cch); + VEC_safe_push (chain_p, heap, chains, cch); + break; + } + } + } + } + + /* Sets alias information based on data reference DR for REF, + if necessary. / + + static void + set_alias_info (tree ref, struct data_reference dr) + { + tree var; + tree tag = DR_MEMTAG (dr); + + gcc_assert (tag != NULL_TREE); + + ref = get_base_address (ref); + if (!ref || !INDIRECT_REF_P (ref)) + return; + + var = SSA_NAME_VAR (TREE_OPERAND (ref, 0)); + if (var_ann (var)->symbol_mem_tag) + return; + + if (!MTAG_P (tag)) + new_type_alias (var, tag, ref); + else + var_ann (var)->symbol_mem_tag = tag; + + var_ann (var)->subvars = DR_SUBVARS (dr); + } + + / Prepare initializers for CHAIN in LOOP. Returns false if this is + impossible because one of these initializers may trap, true otherwise. / + + static bool + prepare_initializers_chain (struct loop loop, chain_p chain) + { + unsigned i, n = (chain->type == CT_INVARIANT) ? 1 : chain->length; + struct data_reference data_ref = get_chain_root (chain)->ref; + tree init, ref = DR_REF (data_ref), stmts; + dref laref; + edge entry = loop_preheader_edge (loop); + + /* Find the initializers for the variables, and check that they cannot + trap. / + chain->inits = VEC_alloc (tree, heap, n); + for (i = 0; i < n; i++) + VEC_quick_push (tree, chain->inits, NULL_TREE); + + / If we have replaced some looparound phi nodes, use their initializers + instead of creating our own. / + for (i = 0; VEC_iterate (dref, chain->refs, i, laref); i++) + { + if (TREE_CODE (laref->stmt) != PHI_NODE) + continue; + + gcc_assert (laref->distance > 0); + VEC_replace (tree, chain->inits, n - laref->distance, + PHI_ARG_DEF_FROM_EDGE (laref->stmt, entry)); + } + + for (i = 0; i < n; i++) + { + if (VEC_index (tree, chain->inits, i) != NULL_TREE) + continue; + + init = unshare_expr (ref); + ref_at_iteration (loop, init, (int) i - n); +
+ if (!chain->all_always_accessed && tree_could_trap_p (init)) + return false; + + init = force_gimple_operand (init, &stmts, false, NULL_TREE); + if (stmts) + { + mark_virtual_ops_for_renaming_list (stmts); + bsi_insert_on_edge_immediate (entry, stmts); + } + set_alias_info (init, data_ref); + + VEC_replace (tree, chain->inits, i, init); + } + + return true; + } + + / Prepare initializers for CHAINS in LOOP, and free chains that cannot + be used because the initializers might trap. / + + static void + prepare_initializers (struct loop loop, VEC (chain_p, heap) chains) + { + chain_p chain; + unsigned i; + + for (i = 0; i < VEC_length (chain_p, chains); ) + { + chain = VEC_index (chain_p, chains, i); + if (prepare_initializers_chain (loop, chain)) + i++; + else + { + release_chain (chain); + VEC_unordered_remove (chain_p, chains, i); + } + } + } + + /* Performs predictive commoning for LOOP. Returns true if LOOP was + unrolled. / + + static bool + tree_predictive_commoning_loop (struct loop loop) + { + VEC (data_reference_p, heap) datarefs; + VEC (ddr_p, heap) dependences; + struct component components; + VEC (chain_p, heap) chains = NULL; + unsigned unroll_factor; + struct tree_niter_desc desc; + bool unroll = false; + edge exit; + bitmap tmp_vars; + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Processing loop %d\n", loop->num); + + / Find the data references and split them into components according to their + dependence relations. / + datarefs = VEC_alloc (data_reference_p, heap, 10); + dependences = VEC_alloc (ddr_p, heap, 10); + compute_data_dependences_for_loop (loop, true, &datarefs, &dependences); + if (dump_file && (dump_flags & TDF_DETAILS)) + dump_data_dependence_relations (dump_file, dependences); + + components = split_data_refs_to_components (loop, datarefs, dependences); + free_dependence_relations (dependences); + if (!components) + { + free_data_refs (datarefs); + return false; + } + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Initial state:\n\n"); + dump_components (dump_file, components); + } + + / Find the suitable components and split them into chains. / + components = filter_suitable_components (loop, components); + + tmp_vars = BITMAP_ALLOC (NULL); + looparound_phis = BITMAP_ALLOC (NULL); + determine_roots (loop, components, &chains); + release_components (components); + + if (!chains) + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Predictive commoning failed: no suitable chains\n"); + goto end; + } + prepare_initializers (loop, chains); + + / Try to combine the chains that are always worked with together. / + try_combine_chains (&chains); + + if (dump_file && (dump_flags & TDF_DETAILS)) + { + fprintf (dump_file, "Before commoning:\n\n"); + dump_chains (dump_file, chains); + } + + / Determine the unroll factor, and if the loop should be unrolled, ensure + that its number of iterations is divisible by the factor. / + unroll_factor = determine_unroll_factor (chains); + scev_reset (); + unroll = should_unroll_loop_p (loop, unroll_factor, &desc); + exit = single_dom_exit (loop); + + / Execute the predictive commoning transformations, and possibly unroll the + loop. / + if (unroll) + { + struct epcc_data dta; + + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, "Unrolling %u times.\n", unroll_factor); + + dta.chains = chains; + dta.tmp_vars = tmp_vars; +
+ update_ssa (TODO_update_ssa_only_virtuals); + tree_transform_and_unroll_loop (loop, unroll_factor, exit, &desc, + execute_pred_commoning_cbck, &dta); + eliminate_temp_copies (loop, tmp_vars); + } + else + { + if (dump_file && (dump_flags & TDF_DETAILS)) + fprintf (dump_file, + "Executing predictive commoning without unrolling.\n"); + execute_pred_commoning (loop, chains, tmp_vars); + } + + end: ; + release_chains (chains); + free_data_refs (datarefs); + BITMAP_FREE (tmp_vars); + BITMAP_FREE (looparound_phis); + + if (name_expansions) + { + htab_delete (name_expansions); + name_expansions = NULL; + } + + return unroll; + } + + / Runs predictive commoning. / + + void + tree_predictive_commoning (void) + { + bool unrolled = false; + struct loop loop; + loop_iterator li; + + initialize_original_copy_tables (); + FOR_EACH_LOOP (li, loop, LI_ONLY_INNERMOST) + { + unrolled |= tree_predictive_commoning_loop (loop); + } + + if (unrolled) + { + scev_reset (); + cleanup_tree_cfg_loop (); + } + free_original_copy_tables (); + } Index: common.opt

* common.opt (revision 121952) --- common.opt (working copy) *********** fpie * 719,724 **** --- 719,728 ---- Common Report Var(flag_pie,1) VarExists Generate position-independent code for executables if possible (small mode)
+ fpredictive-commoning + Common Report Var(flag_predictive_commoning) + Run predictive commoning optimization. + fprefetch-loop-arrays Common Report Var(flag_prefetch_loop_arrays) Optimization Generate prefetch instructions, if available, for arrays in loops Index: tree-flow.h

* tree-flow.h (revision 121952) --- tree-flow.h (working copy) *********** extern bool cleanup_tree_cfg_loop (void) * 674,679 **** --- 674,680 ----
/* In tree-pretty-print.c. / extern void dump_generic_bb (FILE , basic_block, int, int); + extern const char op_symbol_code (enum tree_code);
/ In tree-dfa.c */ extern var_ann_t create_var_ann (tree); ************* unsigned int tree_unroll_loops_completel * 861,866 **** --- 862,868 ---- unsigned int tree_ssa_prefetch_arrays (void); unsigned int remove_empty_loops (void); void tree_ssa_iv_optimize (void); + void tree_predictive_commoning (void);
bool number_of_iterations_exit (struct loop , edge, struct tree_niter_desc niter, bool); ************* void tree_transform_and_unroll_loop (str * 906,911 **** --- 908,914 ---- edge, struct tree_niter_desc , transform_callback, void ); bool contains_abnormal_ssa_name_p (tree); + bool stmt_dominates_stmt_p (tree, tree);
/ In tree-ssa-threadedge.c / extern bool potentially_threadable_block (basic_block); ************* enum move_pos * 923,928 **** --- 926,932 ---- MOVE_POSSIBLE /* Unlimited movement. / }; extern enum move_pos movement_possibility (tree); + char get_lsm_tmp_name (tree, unsigned);
/ The reasons a variable may escape a function. / enum escape_type Index: Makefile.in

* Makefile.in (revision 121952) --- Makefile.in (working copy) *********** OBJS-common =
* 1093,1098 --- 1093,1099 ---- tree-optimize.o
tree-outof-ssa.o
tree-phinodes.o
+ tree-predcom.o
tree-pretty-print.o
tree-profile.o
tree-scalar-evolution.o
********* tree-ssa-loop-prefetch.o: tree-ssa-loop- * 2135,2140 --- 2136,2145 ---- tree-pass.h (GGCH)(GGC_H) (GGCH)(RECOG_H) insn-config.h (HASHTABH)(HASHTAB_H) (HASHTABH)(SCEV_H)
(CFGLOOPH)(CFGLOOP_H) (CFGLOOPH)(PARAMS_H) langhooks.h $(BASIC_BLOCK_H) hard-reg-set.h
tree-chrec.h toplev.h langhooks.h $(TREE_INLINE_H) + tree-predcom.o: tree-predcom.c (CONFIGH)(CONFIG_H) (CONFIGH)(SYSTEM_H) (TREEH)(TREE_H) (TREEH)(TM_P_H)
+ (CFGLOOPH)(CFGLOOP_H) (CFGLOOPH)(TREE_FLOW_H) (GGCH)(GGC_H) (GGCH)(TREE_DATA_REF_H) $(SCEV_H)
+ (PARAMSH)(PARAMS_H) (PARAMSH)(DIAGNOSTIC_H) tree-pass.h $(TM_H) coretypes.h tree-affine.h
+ tree-inline.h tree-ssa-loop-ivopts.o : tree-ssa-loop-ivopts.c (TREEFLOWH)(TREE_FLOW_H) (TREEFLOWH)(CONFIG_H)
(SYSTEMH)(SYSTEM_H) (SYSTEMH)(RTL_H) (TREEH)(TREE_H) (TREEH)(TM_P_H) (CFGLOOPH)(CFGLOOP_H) (CFGLOOPH)(EXPR_H)
output.h (DIAGNOSTICH)(DIAGNOSTIC_H) (DIAGNOSTICH)(TIMEVAR_H) (TMH)coretypes.h(TM_H) coretypes.h (TMH)coretypes.h(TREE_DUMP_H)
********* tree-ssa-loop-ivopts.o : tree-ssa-loop-i * 2142,2148 **** (CFGLOOPH)(CFGLOOP_H) (CFGLOOPH)(PARAMS_H) langhooks.h $(BASIC_BLOCK_H) hard-reg-set.h
tree-chrec.h $(VARRAY_H) tree-affine.h pointer-set.h tree-affine.o : tree-affine.c tree-affine.h $(CONFIG_H)
! (SYSTEMH)(SYSTEM_H) (SYSTEMH)(RTL_H) (TREEH)(TREE_H) (TREEH)(TM_P_H)
output.h (DIAGNOSTICH)(DIAGNOSTIC_H) (DIAGNOSTICH)(TM_H) coretypes.h $(TREE_DUMP_H) tree-ssa-loop-manip.o : tree-ssa-loop-manip.c (TREEFLOWH)(TREE_FLOW_H) (TREEFLOWH)(CONFIG_H)
(SYSTEMH)(SYSTEM_H) (SYSTEMH)(RTL_H) (TREEH)(TREE_H) (TREEH)(TM_P_H) $(CFGLOOP_H)
--- 2147,2153 ---- (CFGLOOPH)(CFGLOOP_H) (CFGLOOPH)(PARAMS_H) langhooks.h $(BASIC_BLOCK_H) hard-reg-set.h
tree-chrec.h $(VARRAY_H) tree-affine.h pointer-set.h tree-affine.o : tree-affine.c tree-affine.h $(CONFIG_H)
! (SYSTEMH)(SYSTEM_H) (SYSTEMH)(RTL_H) (TREEH)(TREE_H) (TREEH)(TM_P_H) $(TREE_GIMPLE_H)
output.h (DIAGNOSTICH)(DIAGNOSTIC_H) (DIAGNOSTICH)(TM_H) coretypes.h $(TREE_DUMP_H) tree-ssa-loop-manip.o : tree-ssa-loop-manip.c (TREEFLOWH)(TREE_FLOW_H) (TREEFLOWH)(CONFIG_H)
(SYSTEMH)(SYSTEM_H) (SYSTEMH)(RTL_H) (TREEH)(TREE_H) (TREEH)(TM_P_H) $(CFGLOOP_H)
Index: passes.c

*** passes.c (revision 121952) --- passes.c (working copy) *************** init_optimization_passes (void) *** 584,590 **** --- 585,593 ---- struct tree_opt_pass **p = &pass_tree_loop.sub; NEXT_PASS (pass_tree_loop_init); NEXT_PASS (pass_copy_prop);

  NEXT_PASS (pass_dce_loop);
  NEXT_PASS (pass_lim);

  NEXT_PASS (pass_predcom);
  NEXT_PASS (pass_tree_unswitch);
  NEXT_PASS (pass_scev_cprop);
  NEXT_PASS (pass_empty_loop);

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- Re: [patch] Predictive commoning, updated
  * From: Dorit Nuzman

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Zdenek Dvorak - [patch] Predictive commoning, updated (original) (raw)

Index: passes.c

Index: doc/passes.texi

*** opts.c (revision 121952) --- opts.c (working copy) *************** decode_options (unsigned int argc, const *** 501,506 **** --- 501,507 ---- if (optimize >= 3) { + flag_predictive_commoning = 1; flag_inline_functions = 1; flag_unswitch_loops = 1; flag_gcse_after_reload = 1; Index: timevar.def

* opts.c (revision 121952) --- opts.c (working copy) *********** decode_options (unsigned int argc, const * 501,506 **** --- 501,507 ----
if (optimize >= 3) { + flag_predictive_commoning = 1; flag_inline_functions = 1; flag_unswitch_loops = 1; flag_gcse_after_reload = 1; Index: timevar.def