| Issue |
71280
|
| Summary |
clang is suboptimal for `(a % b) lt/ge (b-1)` where b is a power of 2
|
| Labels |
clang
|
| Assignees |
|
| Reporter |
k-arrows
|
Example-1 (b=512, "less than")
https://godbolt.org/z/Tdc6onb6e
https://alive2.llvm.org/ce/z/wvSEvC
```cpp
int foo(int a)
{
return (a % 512) < 511;
}
int bar(int a)
{
return (a & -2147483137) != 511;
}
```
Example-2 (b=8, "greater than or equal to")
https://godbolt.org/z/cxdveoT1n
https://alive2.llvm.org/ce/z/sm3xs5
```cpp
int baz(int a)
{
return (a % 8) >= 7;
}
int qux(int a)
{
return (a & -2147483641) == 7;
}
```
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