Fix AVX512 build with older compilers

mstembera · noobpwnftw · commit d7b11485f3d5 · 2020-08-15T22:59:01.000+08:00
avoids an intrinsic that is missing in gcc < 10. For this target, might trigger another gcc bug on windows that requires up-to-date gcc 8, 9, or 10, or usage of clang. Fixes official-stockfish#2975 closes official-stockfish#2976 No functional change
diff --git a/src/Makefile b/src/Makefile
@@ -416,7 +416,7 @@ endif
 ifeq ($(avx512),yes)
 	CXXFLAGS += -DUSE_AVX512
 	ifeq ($(comp),$(filter $(comp),gcc clang mingw))
-		CXXFLAGS += -mavx512bw
+		CXXFLAGS += -mavx512f -mavx512bw
 	endif
 endif
 
diff --git a/src/nnue/layers/affine_transform.h b/src/nnue/layers/affine_transform.h
@@ -126,8 +126,7 @@ namespace Eval::NNUE::Layers {
             const auto iv256  = reinterpret_cast<const __m256i*>(&input_vector[kNumChunks]);
             const auto row256 = reinterpret_cast<const __m256i*>(&row[kNumChunks]);
             __m256i product256 = _mm256_maddubs_epi16(_mm256_loadA_si256(&iv256[0]), _mm256_load_si256(&row256[0]));
-            product256 = _mm256_madd_epi16(product256, _mm256_set1_epi16(1));
-            sum = _mm512_add_epi32(sum, _mm512_zextsi256_si512(product256));
+            sum = _mm512_add_epi32(sum, _mm512_cvtepi16_epi32(product256));
         }
         output[i] = _mm512_reduce_add_epi32(sum) + biases_[i];
 

Original file line number	Diff line number	Diff line change
`@@ -126,8 +126,7 @@ namespace Eval::NNUE::Layers {`
`126`	`126`	`const auto iv256 = reinterpret_cast<const __m256i*>(&input_vector[kNumChunks]);`
`127`	`127`	`const auto row256 = reinterpret_cast<const __m256i*>(&row[kNumChunks]);`
`128`	`128`	`__m256i product256 = _mm256_maddubs_epi16(_mm256_loadA_si256(&iv256[0]), _mm256_load_si256(&row256[0]));`
`129`		`- product256 = _mm256_madd_epi16(product256, _mm256_set1_epi16(1));`
`130`		`- sum = _mm512_add_epi32(sum, _mm512_zextsi256_si512(product256));`
	`129`	`+ sum = _mm512_add_epi32(sum, _mm512_cvtepi16_epi32(product256));`
`131`	`130`	`}`
`132`	`131`	`output[i] = _mm512_reduce_add_epi32(sum) + biases_[i];`
`133`	`132`