Richard Henderson - alpha bootstrap fix (original) (raw)

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• To: jh at suse dot cz, gcc-patches at gcc dot gnu dot org
• Subject: alpha bootstrap fix
• From: Richard Henderson
• Date: Sun, 20 May 2001 18:32:19 -0700

Thu May 17 23:19:46 CEST 2001 Jan Hubicka jh@suse.cz

    * combine.c (combine_simplify_rtx): Use swap_commutative_operands_p.
    (gen_binary): Likewise.
    * optabs.c (emit_cmp_and_jump_insns, emit_conditional_move): Likewise.
    * simplify-rtx.c (simplify_gen_binary,
    simplify_gen_relational): Likewise.

The change to emit_cmp_and_jump_insns, at minimum, is incorrect. This is used e.g. by compare_from_rtx from emit_store_flag to generate setcc instructions. We have no way of mentioning this change of comparison code to upper layers, resulting in bad code.

A reduced test case is

static unsigned int expr_hash_table_size = 1;

int main () { int del = 1; unsigned int i = 0;

if (i < expr_hash_table_size && del) exit (0); abort (); }

Fixed thus.

r~

* optabs.c (emit_cmp_and_jump_insns): Don't swap commutative
operands unless the operation is commutative.

Index: optabs.c

RCS file: /cvs/gcc/gcc/gcc/optabs.c,v retrieving revision 1.97 diff -c -p -d -r1.97 optabs.c *** optabs.c 2001/05/17 21:21:21 1.97 --- optabs.c 2001/05/21 01:22:23 *************** emit_cmp_and_jump_insns (x, y, compariso *** 3289,3301 **** { rtx op0; rtx op1; !
! if (swap_commutative_operands_p (x, y)) { /* Swap operands and condition to ensure canonical RTL. */ op0 = y; op1 = x;

•   comparison = swap_condition (comparison);
  }

  else {

--- 3289,3304 ---- { rtx op0; rtx op1; ! ! /* We may not swap in the general case, since this is called from ! compare_from_rtx, and we have no way of reporting the changed ! comparison code. / ! if (comparison == swap_condition (comparison) ! && swap_commutative_operands_p (x, y)) { / Swap operands and condition to ensure canonical RTL. */ op0 = y; op1 = x; } else {

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