Add support for simple SIMD features detection in autoconf (PoC) #125011
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| #include <stdbool.h> | ||
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| typedef struct { | ||
| bool sse, sse2, sse3, sse41, sse42, avx, avx2, avx512vbmi; |
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It's suggested that you define sse and and separately, which will be more intuitive.
bool sse, ...;
bool avx, ...;
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Yes and I'll add some comments.
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| #include <stdbool.h> | ||
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| #if defined(__x86_64__) && defined(__GNUC__) |
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Is this the unique header file of the GNU-collection?
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That's the only one containing __cpuid_count.
| edx7 = info7[3]; | ||
| #else | ||
| // use (void) expressions to avoid warnings | ||
| (void) eax1; (void) ebx1; (void) ecx1; (void) edx1; |
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No. I don't want to add an unnecessary additional macr.
| flags->sse = (edx1 & EDX1_SSE) != 0; | ||
| #else | ||
| flags->sse = false; | ||
| #endif | ||
| #ifdef CAN_COMPILE_SIMD_SSE2_INSTRUCTIONS | ||
| flags->sse2 = (edx1 & EDX1_SSE2) != 0; | ||
| #else | ||
| flags->sse2 = false; | ||
| #endif | ||
| #ifdef CAN_COMPILE_SIMD_SSE3_INSTRUCTIONS | ||
| flags->sse3 = (ecx1 & ECX1_SSE3) != 0; | ||
| #else | ||
| #endif | ||
| flags->sse3 = false; | ||
| #ifdef CAN_COMPILE_SIMD_SSE4_1_INSTRUCTIONS | ||
| flags->sse41 = (ecx1 & ECX1_SSE4_1) != 0; | ||
| #else | ||
| flags->sse41 = false; | ||
| #endif | ||
| #ifdef CAN_COMPILE_SIMD_SSE4_2_INSTRUCTIONS | ||
| flags->sse42 = (ecx1 & ECX1_SSE4_2) != 0; | ||
| #else | ||
| flags->sse42 = false; | ||
| #endif | ||
| #ifdef CAN_COMPILE_SIMD_AVX_INSTRUCTIONS | ||
| flags->avx = (ecx1 & ECX1_AVX) != 0; | ||
| #else | ||
| flags->avx = false; | ||
| #endif | ||
| #ifdef CAN_COMPILE_SIMD_AVX2_INSTRUCTIONS | ||
| flags->avx2 = (ebx7 & EBX7_AVX2) != 0; |
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_Bool is no different from int. In fact, this redundant can be removed ！=.
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It can be safely converted.
| #include "Python.h" | ||
| #include "pycore_cpuinfo.h" | ||
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| #include <stdbool.h> |
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It seems that stdbool has been defined in Python.h Maybe this can be removed it.
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I prefer not to include the entire Python if I don't need to. And I prefer explicit includes.
In #124951, there has been some initial discussion on improving the performances of base64 and possibly
{bytes,str}.translateusing SIMD instructions.More generally, if we want to use specific SIMD instructions, it'd be good if we at least know whether we can use them or not. This PR is a PoC (hence the draft and the skip news/issue for now just to make the CI green for those checks).
Note that the detection is essentially based on what was done in the blake2 module (though the flags being detected are different in this case). This PoC shows that we can easily add flags and compiler flags if we need them.
Note
The detection of a wider large family of CPUs (here we just assume Intel for simplicity and because we don't want to be overcomplicated for now) is still an ongoing work.
cc @gpshead