| Issue |
77171
|
| Summary |
Other patterns where clang is not optimal for powi (with fast-math)
|
| Labels |
clang
|
| Assignees |
|
| Reporter |
k-arrows
|
There have been a few missed-optimization issues with `pow(x, n)` where `n` is an integer. Here, I will provide some other patterns which aren't mentioned in the existing issues.
Test case(1):
https://godbolt.org/z/WGdxTWK6G
```c
#include<math.h>
double f1(double a)
{
return pow(a, 5) / pow(a, 2);
}
double g1(double a)
{
return pow(a, 3);
}
```
If we rewrite `/ pow(a, 2)` as ` * pow(a, -2)`, we won't have a problem.
Test case(2):
https://godbolt.org/z/W6nWzhfss
```c
#include<math.h>
double f2(double a, double b)
{
return pow(a, -2) * pow(b, -2);
}
double g2(double a, double b)
{
return pow(a * b, -2);
}
```
Related existing issues:
https://github.com/llvm/llvm-project/issues/67216
https://github.com/llvm/llvm-project/issues/69862
![]()
_______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
