4.0 regression][m68k] m68k-elf-gcc -m5200 produces erroneous SImode set of short varaible on stack (original) (raw)

| Description peter.barada 2002-10-22 11:46:00 UTC Compile the attached test files with: m68k-elf-gcc -O2 -fno-common -ffixed-a2 -m5200 -S -o yy.s yy.c -dp -da And in the ouptut of yy.c.21.greg, you'll find: (insn 492 283 284 (set (reg:SI 1 %d1) (const_int 1 [0x1])) 30 {*m68k.md:993} (nil) (nil)) (insn 284 492 285 (set (mem:SI (plus:SI (reg/f:SI 14 %a6) (const_int -40 [0xffffffd8])) [26 rotate S4 A16]) (plus:SI (mem:SI (plus:SI (reg/f:SI 14 %a6) (const_int -40 [0xffffffd8])) [26 rotate S4 A16]) (reg:SI 1 %d1))) 99 {*addsi3_5200} (nil) (nil)) But the 'rotate' variable is a *short*, so the 'set(mem:SI' will overwrite the adjacent variable on the stack. In fact the statement *increments* the 'fs' varaible which is at offset -38 from the frame... Release: gcc-3.2 Environment: --target=m68k-elf How-To-Repeat: m68k-elf-gcc -O2 -fno-common -ffixed-a2 -m5200 -S -o yy.s yy.c -dp -da Comment 1 pbarada 2002-10-29 18:49:50 UTC From: Peter Barada <pbarada@mail.wm.sps.mot.com> To: gcc-gnats@gcc.gnu.org Cc: Peter.Barada@motorola.com Subject: Re: target/8309:m68k-elf-gcc -m5200 produces erroneous SImode set of short varaible on stack Date: Tue, 29 Oct 2002 18:49:50 -0500 I've culled a much smaller testcase that fails on the trunk and the 3.2 branch. I'm backsearching the trunk to see when this bug was introduced, and have found the bug existed back at 2000/02/01, but doesn't show itself at 1999/01/01, so I'll try to narrow it down. #define SMALLER_TESTCASE /* make the testcase *very* small */ extern void foo(); void foo(a,b,c,d,e,f,g,h,i,j,k,l) short a,b,c,d,e,f,g,h,i,j,k,l; { short m,n,o,p,q,r,s #ifndef SMALLER_TESTCASE ,t,u,v #endif ; for (m=0; m<a; ++m) { for (n=m; n<b; ++n) { for (o=n; o<c; ++o) { for (p=o; p<d; ++p) { for (q=p; q<e; ++q) { for (r=q; r<f; ++r) { for (s=r; s<g; ++s) { #ifndef SMALLER_TESTCASE for (t=s; t<h; ++t) { for (u=t; u<i; ++u) { for (v=u; v<j; ++v) { #endif foo2(m,n,o,p,q ,r,s #ifndef SMALLER_TESTCASE ,t,u,v #endif ); } } #ifndef SMALLER_TESTCASE } } } #endif } } } } } } Comment 3 Giovanni Bajo 2003-05-10 07:48:19 UTC State-Changed-From-To: open->feedback State-Changed-Why: See Dara's question. Comment 4 pbarada 2003-05-12 11:48:55 UTC From: Peter Barada <pbarada@mail.wm.sps.mot.com> To: giovannibajo@libero.it, Peter.Barada@motorola.com, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org, gcc-gnats@gcc.gnu.org Cc: Subject: Re: target/8309: [3.2/? regression][m68k] m68k-elf-gcc -m5200 produces erroneous SImode set of short varaible on stack Date: Mon, 12 May 2003 11:48:55 -0400 >you reported this bug about 6 months ago. Can you confirm whether it's >still present in 3.3 branch and mainline today? Thanks, Ok, I pulled out the prerelease of gcc-3.3 and I still see this problem: [pbarada: /tmp] > /tmp/m68k-elf-3.3/bin/m68k-elf-gcc -v Reading specs from /tmp/m68k-elf-3.3/lib/gcc-lib/m68k-elf/3.3/specs Configured with: /home/pbarada/work/cvs-wavemark/cross-linux-tools/gcc-3.3-20030508/configure --target=m68k-elf --prefix=/tmp/m68k-elf-3.3 --enable-languages=c --with-local-prefix=/tmp/m68k-elf-3.3/m68k-elf --without-headers --with-newlib --disable-shared --verbose Thread model: single gcc version 3.3 20030509 (prerelease) [pbarada: /tmp] > /tmp/m68k-elf-3.3/bin/m68k-elf-gcc -O2 -fno-common -ffixed-a2 -m5200 -S -o yy.s yy.c -dp -da yy.c.11.gcse: (insn 230 228 231 9 0x4001f420 (set (reg:SI 94) (plus:SI (subreg:SI (reg/v:HI 40) 0) (const_int 1 [0x1]))) 100 {*addsi3_5200} (nil) (nil)) (insn 231 230 232 9 0x4001f420 (set (reg/v:HI 40) (subreg:HI (reg:SI 94) 2)) 33 {*m68k.md:1024} (nil) (nil)) yy.c.23.lreg: (insn 231 230 232 10 0x4001f420 (set (subreg:SI (reg/v:HI 40) 0) (plus:SI (subreg:SI (reg/v:HI 40) 0) (const_int 1 [0x1]))) 100 {*addsi3_5200} (nil) (nil)) (insn 232 231 235 10 0x4001f420 (set (reg/f:SI 15 %sp) (plus:SI (reg/f:SI 15 %sp) (const_int 8 [0x8]))) 100 {*addsi3_5200} (nil) (nil)) yy.c.24.greg: (note 230 228 371 10 NOTE_INSN_DELETED) (insn 371 230 231 10 (nil) (set (reg:SI 1 %d1) (const_int 1 [0x1])) 30 {*m68k.md:993} (nil) (nil)) (insn 231 371 232 10 0x4001f420 (set (mem:SI (plus:SI (reg/f:SI 14 %a6) (const_int -38 [0xffffffda])) [23 rotate S4 A16]) (plus:SI (mem:SI (plus:SI (reg/f:SI 14 %a6) (const_int -38 [0xffffffda])) [23 rotate S4 A16]) (reg:SI 1 %d1))) 100 {*addsi3_5200} (nil) (nil)) Note that in yy.c.11.gcse insn 231 was (set (mem:HI...)), and in yy.c.24.greg is (set (mem:SI...)) Comment 5 pbarada 2003-05-12 15:51:26 UTC From: Peter Barada <pbarada@mail.wm.sps.mot.com> To: giovannibajo@libero.it, Peter.Barada@motorola.com, gcc-bugs@gcc.gnu.org, gcc-gnats@gcc.gnu.org Cc: Subject: Re: target/8309: [3.2/? regression][m68k] m68k-elf-gcc -m5200 produces erroneous SImode set of short varaible on stack Date: Mon, 12 May 2003 15:51:26 -0400 Ist still broken on the mainline: [pbarada: /tmp] > /home/mylocal/uberbaum-m68k-elf/bin/m68k-elf-gcc -v Reading specs from /home/mylocal/uberbaum-m68k-elf/lib/gcc-lib/m68k-elf/3.4/specs Configured with: /home/pbarada/work/cvs-gnu/uberbaum/configure --target=m68k-elf --prefix=/home/mylocal/uberbaum-m68k-elf --with-gcc-version-trigger=/home/pbarada/work/cvs-gnu/uberbaum/gcc/version.c : (reconfigured) : (reconfigured) /home/pbarada/work/cvs-gnu/uberbaum/configure --target=m68k-elf --prefix=/home/mylocal/uberbaum-m68k-elf --with-gcc-version-trigger=/home/pbarada/work/cvs-gnu/uberbaum/gcc/version.c --enable-languages=c Thread model: single gcc version 3.4 20030512 (experimental) [pbarada: /tmp] > /home/mylocal/uberbaum-m68k-elf/bin/m68k-elf-gcc -O2 -fno-common -ffixed-a2 -m5200 -S -o yy.s yy.c -dp -da yy.c.25.lreg: (insn 230 229 231 10 0x4009486c (set (subreg:SI (reg/v:HI 40 [ rotate ]) 0) (plus:SI (subreg:SI (reg/v:HI 40 [ rotate ]) 0) (const_int 1 [0x1]))) 100 {*addsi3_5200} (nil) (nil)) yy.c.26.greg: (insn 374 229 230 10 (nil) (set (reg:SI 1 %d1) (const_int 1 [0x1])) 30 {*m68k.md:993} (nil) (nil)) (insn 230 374 231 10 0x4009486c (set (mem:SI (plus:SI (reg/f:SI 14 %a6) (const_int -38 [0xffffffda])) [23 rotate+0 S4 A16]) (plus:SI (mem:SI (plus:SI (reg/f:SI 14 %a6) (const_int -38 [0xffffffda])) [23 rotate+0 S4 A16]) (reg:SI 1 %d1))) 100 {*addsi3_5200} (nil) (nil)) Comment 6 Steven Bosscher 2003-05-13 06:21:31 UTC State-Changed-From-To: feedback->analyzed State-Changed-Why: With small testcase Comment 7 Drea Pinski 2003-05-26 01:32:58 UTC see comments for why I changed this to a regression. Comment 8 Falk Hueffner 2003-06-21 11:07:39 UTC Maybe it's just me, but just from looking at the RTL I'm not certain there's a bug here. Just writing to a short stack slot in SI mode looks just fine to me, since shorts are padded to 4 bytes on the stack on m68k, or it might be the result of store merging (except that we don't do that). So is there any test case with observably wrong behaviour? Falk Comment 9 Mark Mitchell 2003-07-11 23:01:12 UTC Postoned until GCC 3.3.2; m68k is not a primary platform. Comment 10 Dara Hazeghi 2003-08-24 18:20:31 UTC Dunno why this is in waiting, but it shouldn't be. Should be... Comment 11 Dara Hazeghi 2003-08-24 18:20:52 UTC Unconfirmed. Comment 12 Drea Pinski 2003-08-24 18:23:14 UTC Dara the reason why this was in waiting was this question: "So is there any test case with observably wrong behaviour?" So the question still stands. Comment 13 Drea Pinski 2003-09-05 01:51:56 UTC No feedback in 3 months (T-16 days). Comment 14 Fabrizio Pirovano 2004-03-08 15:57:10 UTC We are using rtems-4.6.0, opt "rtems-4.6" with GNU gcc compiler 3.2.3 on MCF5272 target and we encountered again a problem that seems PR 8309. This problem is very critical because all the code generated for coldfire family is unreliable and to find the cause of possible malfunction is very hard. Here a short description of we encountered: We compile with -O4 -fno-force-mem and a local variable declared as byte is managed in wrong mode. Here we show the C-code and the assembler generated by compiler: pInfo->InfoHw[0].Offset = offset+ p->Reg; move.b -0x0B(a6),d0 ; offset(a6),d0 move.b d0,-0x0F(a6) ; d0,-15(a6) ;ok is a Byte move.b 0x1(a2),d6 ; 1(a2),d6 ext.w d6 add.l -0x10(a6),d6 ;add.w doesn't exist in coldfire move.w d6,0x6(a1) ;and using add.l it gets values ;stored from -0x10(a6) to -0x0d(a6) If we change the declaration of the local variable , from byte to short, the code becomes: pInfo->InfoHw[0].Offset = offset+p->Reg move.b 0x1(a2),d7 ; 1(a2),d7 ext.w d7 add.l a5,d7 ; offset,d7 move.w d7,0x6(a1) ; d7,EXTENDSFDF(a1) In this case compiler uses a register for the local variable and then the problem disappear. Comment 15 Kazu Hirata 2004-03-08 16:06:53 UTC Could you post a preprocessed testcase if it's not one of those that are mentioned in this PR? Thanks, Comment 17 Giovanni Bajo 2004-06-06 03:44:35 UTC Retargeting to 3.4.1, being a regression on that release branch. Mark, there is a pending patch for this. Comment 18 Mark Mitchell 2004-06-07 14🔞36 UTC I'm not comfortable approving this patch, given that changes to reload have such great potential for causing problems on other targets. However, if someone more comfortable with reload approves the patch -- and tests it on at least one other target where the chnage would apply -- it's OK for 3.4.1. Comment 19 Bernardo Innocenti 2004-06-10 08:03:20 UTC *** Bug 13312 has been marked as a duplicate of this bug. *** Comment 20 Bernardo Innocenti 2004-06-12 01:15:51 UTC Fixed on mainline and 3.4-branch. | | | 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