https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111457
Bug ID: 111457
Summary: [14 Regression] Dead Code Elimination Regression since
r14-3407-g936a12331a2
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: theodort at inf dot ethz.ch
Target Milestone: ---
https://godbolt.org/z/j4M8z8MzK
Given the following code:
void foo(void);
static int a, b, c, d, h;
static short i;
static void e(int f) {
int g = -16;
for (; g != -6; g = g + 5) {
b = 6;
if (!(((f) >= 1) && ((f) <= 26))) {
__builtin_unreachable();
}
f = 0;
for (; f < 26; ++f)
if (a) {
foo();
break;
}
d = 0;
}
}
int main() {
a = 0;
e(0 == i);
h = d;
c = b;
}
gcc-trunk -O2 does not eliminate the call to foo:
main:
movl $0, a(%rip)
pushq %rbx
movl $2, %ebx
.L3:
movl $6, b(%rip)
movl a(%rip), %eax
testl %eax, %eax
je .L2
call foo
.L2:
movl $0, d(%rip)
cmpl $1, %ebx
jne .L4
xorl %eax, %eax
popq %rbx
ret
.p2align 4,,10
.p2align 3
.L4:
movl $1, %ebx
jmp .L3
gcc-13.2.0 -O2 eliminates the call to foo:
main:
movl $0, a(%rip)
xorl %eax, %eax
movl $6, b(%rip)
movl $0, d(%rip)
ret
Bisects to r14-3407-g936a12331a2
