[LoopInterchange] Loops should not interchanged due to control flow #47401
Description
| Bugzilla Link | 48057 |
| Version | trunk |
| OS | Linux |
| Attachments | Added the corresponding IR file |
| Reporter | LLVM Bugzilla Contributor |
Extended Description
$ clang -mllvm -enable-loopinterchange=true -O2 reproducer.c -w && ./a.out
0
$ clang -mllvm -enable-loopinterchange=false -O2 reproducer.c -w && ./a.out
5
$ clang -O0 reproducer.c -w && ./a.out
5
reproducer.c:
#include <stdio.h>
char b[][8] = {{}, {}, {}, {}, {5}, {}, 2, 3};
int c, d;
short e;
static char f() {
for (; c <= 7; c++) {
d = 4;
for (; d; d--)
b[d + 2][c] && (e = b[d][0]);
}
}
int main() {
f();
printf("%d\n", e);
}