| Issue |
168551
|
| Summary |
LLVM generates huge unrolled loop instead of using vector instructions
|
| Labels |
new issue
|
| Assignees |
|
| Reporter |
philnik777
|
```c++
#include <algorithm>
extern char arr[32];
auto test(char c) {
return std::find_if(arr, arr + 26, [&](char v) { return v == c; });
}
```
currently generates a huge unrolled loop instead of generating a few vector instructions that it could be.
```c++
extern char arr[32];
template <class T, int N>
using vec [[clang::ext_vector_type(N)]] = T;
auto test(char c) {
auto match = vec<bool, 26>(__builtin_masked_load(vec<bool, 26>{1}, arr) == c);
return __builtin_clzg(match, 26);
}
```
is equivalent, but generates much better code.
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