How to Load 8 Floats into an __m256 Variable Using AVX Intrinsics?

Loading 8 Floats from Memory into __m256 Variable

Your goal is to replace the float buffer[8] with an intrinsic variable, __m256. Here are the instructions to achieve this:

AVX2 Instructions:

1. Use VPMOVZXBD ymm0, [rsi] to zero-extend the bytes in memory into 32-bit integers.
2. Convert the integers to floats with VCVTDQ2PS ymm0, ymm0.

AVX1 Instructions:

1. Use VPMOVZXBD xmm0, [rsi] to load the first four bytes.
2. Load the next four bytes with VPMOVZXBD xmm1, [rsi 4].
3. Insert the second load into the high 128 bits of ymm0 with VINSERTF128 ymm0, ymm0, xmm1, 1.
4. Convert to floats with VCVTDQ2PS ymm0, ymm0.

Optimization Tips:

• For AVX2, consider using a 128-bit broadcast load and VPMOVZXBD for performance.
• Avoid using VPMOVZXBD ymm, [mem] with intrinsics, as it may lead to missed optimizations.
• For AVX1, use _mm_loadl_epi64 to fold the load into the VPMOVZXBD instruction for optimal code.

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