https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91137
Bug ID: 91137
Summary: Wrong code with -O3
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: vsevolod.livinskij at frtk dot ru
Target Milestone: ---
GCC produces wrong code with –O3.
Reproducer:
#include <stdio.h>
long long a;
unsigned b;
int c[70];
int d[70][70];
int e;
void f(long long *g, int p2) { *g = p2; }
void fn2() {
for (int j = 0; j < 70; j++) {
for (int i = 0; i < 70; i++) {
if (b)
c[i] = 0;
for (int l = 0; l < 70; l++)
d[i][1] = d[l][i];
}
for (int k = 0; k < 70; k++)
e = c[0];
}
}
int main() {
b = 5;
for (int j = 0; j < 70; ++j)
c[j] = 2075593088;
fn2();
f(&a, e);
printf("%lld\n", a);
}
Error:
>$ gcc -O3 repr.c ; ./a.out
2075593088
>$ gcc -O0 repr.c ; ./a.out
0
GCC version:
gcc version 10.0.0 (Rev: 273261)
This error can also be reproduced with gcc version 7.3.1
