https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110931
Bug ID: 110931
Summary: [14 Regression] Dead Code Elimination Regression since
r14-2890-gcc2003cd875
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/zPTeo8Mj9
Given the following code:
void foo(void);
static int a = 7, c;
static int *d = &a, *e;
static int **f = &e;
static short g;
static char(h)(char b) {
if (!(((b) >= 1) && ((b) <= 1))) {
__builtin_unreachable();
}
return 0;
}
static void k(unsigned i) {
short j = i;
if (j)
;
else {
h(i);
if ((e && i) <= 0)
;
else
foo();
*f = &c;
}
h(0 >= 0);
}
int main() {
int l = *d;
g = l;
k(g);
}
gcc-trunk -O3 does not eliminate the call to foo:
main:
cmpw $0, a(%rip)
jne .L5
cmpq $0, e(%rip)
je .L6
pushq %rax
call foo
xorl %eax, %eax
movq $c, e(%rip)
popq %rdx
ret
.L6:
movq $c, e(%rip)
.L5:
xorl %eax, %eax
ret
gcc-13.2.0 -O3 eliminates the call to foo:
main:
xorl %eax, %eax
ret
Bisects to r14-2890-gcc2003cd875
