https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113423
Bug ID: 113423
Summary: Missed Optimization: potential redundant load
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: carnet at student dot ethz.ch
Target Milestone: ---
https://godbolt.org/z/jbbEPePhv
Source Code:
int a;
int *b;
int c = 0;
void foo() {
if (b)
c = 3;
a = c;
}
int bar(){
return c;
}
foo:
cmpq $0, b(%rip)
movl c(%rip), %eax <========= eax is overwritten when the jump is
not taken, potentially redundant load
je .L3
movl $3, c(%rip)
movl $3, %eax
.L3:
movl %eax, a(%rip)
ret
%eax is written before the branch. If the branch is not taken, eax is
overwritten. Which makes the highlighted load potentially unnecessary.
