https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96272
Bug ID: 96272
Summary: Failure to optimize overflow check
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: gabravier at gmail dot com
Target Milestone: ---
static inline unsigned f(unsigned a, unsigned b)
{
if (b > UINT_MAX - a)
return UINT_MAX;
return a + b;
}
With -O3, LLVM outputs this:
f(unsigned int, unsigned int):
add edi, esi
mov eax, -1
cmovae eax, edi
ret
GCC outputs this:
f(unsigned int, unsigned int):
mov eax, edi
not eax
add edi, esi
cmp eax, esi
mov eax, -1
cmovnb eax, edi
ret
