llvmbot
commented
2 months ago @llvm/issue-subscribers-clang-modules
Author: Chris Elrod (chriselrod)
That is, code using `immintrin.h` tends to fail to compile when using modules while working fine with headers.
I'll try to produce a minimal example in the next few hours.
For now, I have an example using boost_unordered.
When problems showed up in my own code using intrinsics, I could generally fix it by declaring all arguments as variables, and then passing the lvalues to the intriinsic function.
Hello.cxxm:
```c++
#ifndef USE_HEADERS
module;
#endif
#include <boost/unordered/unordered_flat_map.hpp>
#include <iostream>
#ifndef USE_HEADERS
export module Hello;
export {
#endif
void hello() { std::cout << "Hello World!\n"; }
template <typename K, typename V> using map = boost::unordered_flat_map<K, V>;
#ifndef USE_HEADERS
}
#endif
```
user.cpp:
```c++
#ifndef USE_HEADERS
import Hello;
#else
#include "hello.cxxm"
#endif
int main() {
hello();
int x = 0;
long y = 0;
map<int*,long*> m;
m[&x] = &y;
[[maybe_unused]] auto f = m.find(&x);
return 0;
}
```
Compiling with headers:
```sh
$ clang++ -std=c++23 use.cpp -DUSE_HEADERS -o Hello.out
$ ./Hello.out
Hello World!
```
With modules:
```sh
$ clang++ -std=c++23 --precompile hello.cxxm -o M-hello.pcm
$ clang++ -std=c++23 use.cpp -fmodule-file=Hello=M-hello.pcm M-hello.pcm -o Hello_mod.out
```
results in
```
/usr/include/boost/unordered/detail/foa/core.hpp:293:7: error: no matching function for call to '_mm_cmpeq_epi8'
293 | _mm_cmpeq_epi8(load_metadata(),_mm_setzero_si128()))&0x7FFF;
| ^~~~~~~~~~~~~~
/usr/include/boost/unordered/detail/foa/core.hpp:309:14: note: in instantiation of member function 'boost::unordered::detail::foa::group15<boost::unordered::detail::foa::plain_integral>::match_available' requested here
309 | return (~match_available())&0x7FFF;
```
I could file this as a `boost_unordered` issue or make a PR there, as I've generally found I can work around the problem.
But I'll see about creating a minimal reproducer using `#include <immintrin.h>` directlry that works with headers but fails with modules.
chriselrod
ChuanqiXu9
jiixyj
That is, code using
immintrin.htends to fail to compile when using modules while working fine with headers. I'll try to produce a minimal example in the next few hours. For now, I have an example using boost_unordered. When problems showed up in my own code using intrinsics, I could generally fix it by declaring all arguments as variables, and then passing the lvalues to the intriinsic function.Hello.cxxm:
user.cpp:
Compiling with headers:
With modules:
results in
I could file this as a
boost_unorderedissue or make a PR there, as I've generally found I can work around the problem. But I'll see about creating a minimal reproducer using#include <immintrin.h>directlry that works with headers but fails with modules.