https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99117
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|middle-end |libstdc++
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
FRE5 does
<bb 23> [local count: 2736164397]:
# ivtmp.143_71 = PHI <ivtmp.143_186(23), ivtmp.143_187(22)>
_221 = (void *) ivtmp.143_71;
_124 = MEM[(int * *)_221 + 8B];
- _115 = MEM[(const int &)_101];
_162 = MEM[(const int &)_124];
- _140 = _115 + _162;
- *_101 = _140;
+ *_101 = _162;
__p_61 = _101 + 4;
_127 = _124 + 4;
- _131 = MEM[(const int &)__p_61];
_132 = *_127;
- _133 = _131 + _132;
- *__p_61 = _133;
+ *__p_61 = _132;
__p_136 = __p_61 + 4;
D.69731 ={v} {CLOBBER};
ivtmp.143_186 = ivtmp.143_71 + 16;
- if (ivtmp.143_186 != _60)
+ if (_158 != ivtmp.143_186)
goto <bb 23>; [89.00%]
which looks wrong at a first glance. Ah, it's OK because we have
<bb 23> [local count: 2736164397]:
# ivtmp.143_71 = PHI <ivtmp.143_186(23), ivtmp.143_187(22)>
# PT = null { D.69770 } (escaped, escaped heap)
_221 = (void *) ivtmp.143_71;
# PT = nonlocal escaped null { D.69771 } (escaped, escaped heap)
_124 = MEM[(int * *)_221 + 8B clique 11 base 0];
_115 = MEM[(const int &)_101 clique 11 base 0];
_162 = MEM[(const int &)_124 clique 11 base 0];
_140 = _115 + _162;
MEM[(int *)_101 clique 11 base 1] = _140;
# PT = { D.69772 } (escaped, escaped heap)
__p_61 = _101 + 4;
# PT = nonlocal escaped null { D.69771 } (escaped, escaped heap)
_127 = _124 + 4;
_131 = MEM[(const int &)__p_61 clique 11 base 0];
_132 = MEM[(const int &)_127 clique 11 base 0];
_133 = _131 + _132;
MEM[(int *)__p_61 clique 11 base 1] = _133;
# PT = { D.69772 } (escaped, escaped heap)
__p_136 = __p_61 + 4;
D.69731 ={v} {CLOBBER};
ivtmp.143_186 = ivtmp.143_71 + 16;
if (ivtmp.143_186 != _60)
goto <bb 23>; [89.00%]
else
goto <bb 21>; [11.00%]
so the load is from clique 11, base 0 while the store is to clique 11, base 1
so they do not alias because of some __restrict marking. So the issue is
likely
an invalid testcase or bogus annotation in libstdc++
