https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117033
Bug ID: 117033
Summary: GCC trunk emits larger code at -Oz compared to -O2
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: dccitaliano at gmail dot com
Target Milestone: ---
long patatino() {
long x = 0;
for (int i = 0; i < 5; ++i) {
while (x < 37) {
if (x % 4 == 0) {
x += 4;
}
}
}
return x;
}
-Oz:
patatino():
pushq $5
xorl %eax, %eax
popq %rdx
.L5:
cmpq $36, %rax
jg .L7
addq $4, %rax
jmp .L5
.L7:
decl %edx
jne .L5
ret
-O2:
patatino():
movl $40, %eax
ret
https://godbolt.org/z/969sf9cfb
Believe this is a pass ordering problem -- might be that simplifying the loop
isn't always beneficial.
