https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106073
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
See Also| |https://gcc.gnu.org/bugzill
| |a/show_bug.cgi?id=90348
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Options reduced to
-O2 -funroll-loops -fno-tree-vectorize -fdisable-tree-cunrolli
-fdbg-cnt=gimple_unroll:3-6:8-8
in particular reducing late unrolling more will no longer reproduce the issue.
Disabling all threading after cunroll still reproduces the issue, thus
adding
-fdisable-tree-thread2 -fdisable-tree-threadfull2 -fdisable-tree-vrp2
-fdisable-tree-dom3
disabling IVOPTs hides the issue. Making all functions but main static also
still reproduces the issue (so there's just one function left for late opts).
With that simplification
-O2 -funroll-loops -fno-tree-vectorize -fdisable-tree-cunrolli
-fdbg-cnt=gimple_unroll:3-6:8-8 -fdisable-tree-thread2
-fdisable-tree-threadfull2 -fdisable-tree-dom3 -fno-tree-vrp -fdump-tree-all
-fdbg-cnt=ivopts_loop:13-13:15-15
reproduces it, less IVOPTs does not.
So one difference triggering the issue is (good vs bad in .optimized):
@@ -328,20 +326,21 @@
<bb 19> [local count: 60532]:
l = 0;
+ ivtmp.151_212 = (unsigned long) &bf;
+ _507 = ivtmp.151_212 + 56;
<bb 20> [local count: 412224]:
- # ai_lsm.108_510 = PHI <d.13_27(19), _516(21)>
- # ivtmp_511 = PHI <8(19), ivtmp_512(21)>
- ivtmp_512 = ivtmp_511 - 1;
- if (ivtmp_512 != 0)
+ # ivtmp.151_254 = PHI <ivtmp.151_212(19), ivtmp.151_380(21)>
+ if (ivtmp.151_254 != _507)
goto <bb 21>; [89.00%]
else
goto <bb 22>; [11.00%]
<bb 21> [local count: 366880]:
- bf[ai_lsm.108_510][0] = 5;
- bf[ai_lsm.108_510][1] = 5;
- _516 = ai_lsm.108_510 + 1;
+ _506 = (void *) ivtmp.151_254;
+ MEM[(int *)_506] = 5;
+ MEM[(int *)_506 + 4B] = 5;
+ ivtmp.151_380 = ivtmp.151_254 + 8;
goto <bb 20>; [100.00%]
<bb 22> [local count: 45347]:
@@ -353,8 +352,6 @@
<bb 23> [local count: 40253]:
bf ={v} {CLOBBER(eol)};
- ivtmp.132_498 = (unsigned long) &bf;
- _480 = ivtmp.132_498 + 56;
goto <bb 25>; [100.00%]
<bb 24> [local count: 325681]:
@@ -364,8 +361,8 @@
ivtmp.132_245 = ivtmp.132_383 + 8;
<bb 25> [local count: 365933]:
- # ivtmp.132_383 = PHI <ivtmp.132_498(23), ivtmp.132_245(24)>
- if (ivtmp.132_383 != _480)
+ # ivtmp.132_383 = PHI <ivtmp.151_212(23), ivtmp.132_245(24)>
+ if (ivtmp.151_254 != ivtmp.132_383)
goto <bb 24>; [89.00%]
else
goto <bb 26>; [11.00%]
that already causes quite some assembler changes :/
It's still not clear what goes wrong here.
Interestingly again, -fstack-reuse=none avoids the issue. So maybe the
above hints at 'bf' being the issue here:
Partition 3: size 56 align 16
av au bf
Partition 5: size 56 align 16
av
Partition 1: size 44 align 16
at
Partition 2: size 8 align 8
au
