[PATCH] D88396: [X86] Replace movaps with movups when avx is enabled.

[Craig Topper via Phabricator via llvm-commits]

craig.topper added a comment.

In D88396#2302542 <https://reviews.llvm.org/D88396#2302542>, @LuoYuanke wrote:

> I didn't get the error at https://godbolt.org/z/8aGhd5. Another example may like this, an float array is packed in a struct.
>
>   #include <immintrin.h>
>   
>   __m128 value;
>   
>   typedef struct _data_str {
>       int header;
>       float src[400];
>   } data_t;
>   
>   data_t data;
>   
>   void add(__m128* pointer) {
>       value = _mm_add_ps(value, *pointer);
>   }
>   
>   void foo() {
>       for (int i = 0; i < 400; i += 4)
>       add((__m128*)(&data.src[i]));
>   }

Compiling for SSE this code will likely use the memory form of addps which will fault on the misalignment. I know this patch only targets AVX.

I don’t think you can motivate this change by showing what code you want to accept if the code would crash when compiled with the default SSE2 target.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D88396/new/

https://reviews.llvm.org/D88396