https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103534
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |alias, missed-optimization
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Note there is one missing optimization:
D.42086._M_string_length = 0;
MEM[(char_type &)&D.42086 + 16] = 0;
MEM[(struct basic_string *)&D.41925] ={v} {CLOBBER};
MEM[(struct _Alloc_hider *)&D.41925] ={v} {CLOBBER};
MEM[(struct _Alloc_hider *)&D.41925]._M_p = &D.41925.D.33308._M_local_buf;
_69 = operator new (17);
<bb 3> [local count: 1003797485]:
D.41925._M_dataplus._M_p = _69;
D.41925.D.33308._M_allocated_capacity = 16;
__builtin_memcpy (_69, "1234567890123456", 16);
D.41925._M_string_length = 16;
MEM[(char_type &)_69 + 16] = 0;
_75 = D.42086._M_string_length;
__size_76 = _75 + 16;
pretmp_56 = D.42086._M_dataplus._M_p;
if (__size_76 > 16)
goto <bb 4>; [67.00%]
else
goto <bb 12>; [33.00%]
This might be related to that GCC does not handle the operator new better.
Obvious if that missed optimization is fixed, then the warning will be gone.
I also noticed that with -std=c++17 (or before), the constructor for
std::string is not inlined fully for both std::string objects which avoids the
false positive.
This is another case where it is a "maybe" exceeds maximum object size and we
need to come up with a solution for it.
