| Issue |
92719
|
| Summary |
[clang] performance hog at -O2 with clang-14, and 19-init
|
| Labels |
|
| Assignees |
|
| Reporter |
bi6c
|
```c
#include "csmith.h"
int a, b, c = 5;
void d() {
e:
if (safe_add_func_int64_t_s_s(c, c))
goto e;
}
int main() {
for (; a >= 0; a--) {
b = -18;
for (; b != -10; b = safe_add_func_int16_t_s_s(b, 8)) {
d();
}
}
}
```
OS: Ubuntu 22.04.3 LTS.
There is a performance difference when we compile it with (llvmorg-13.0.0) vs. (llvmorg-14.0.0 and llvmorg-19-init) at optimization level "-O2".
```console
$ ../compiler-builds/llvmorg-13.0.0_build/bin/clang -fsanitize=undefined -g -lgcc_s --rtlib=compiler-rt -I/home/csmith/include/csmith-2.3.0 -O2 testcase.c -o exec
$ timeout 2s ./exec
real 0m0.001s
user 0m0.001s
sys 0m0.000s
$ ../compiler-builds/llvmorg-14.0.0_build/bin/clang -fsanitize=undefined -g -lgcc_s --rtlib=compiler-rt -I/home/csmith/include/csmith-2.3.0 -O2 testcase.c -o exec
$ timeout 2s ./exec
real 0m2.000s
user 0m2.000s
sys 0m0.000s
$ ../compiler-builds/llvmorg-19-init_build/bin/clang -fsanitize=undefined -g -lgcc_s --rtlib=compiler-rt -I/home/csmith/include/csmith-2.3.0 -O2 testcase.c -o exec
$ timeout 2s ./exec
real 0m2.000s
user 0m2.000s
sys 0m0.000s
```
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