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remove denormal flushing in fp32tobf16 for avx & avx512

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(cherry picked from commit e6a5a594a7)
This commit is contained in:
Gauri Deshpande
2021-08-09 22:15:21 +00:00
committed by Rasmus Munk Larsen
parent 4e0357c6dd
commit 93bff85a42
4 changed files with 8 additions and 117 deletions
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11
Eigen/src/Core/arch/AVX/PacketMath.h
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@@ -1274,12 +1274,7 @@ EIGEN_STRONG_INLINE Packet8f Bf16ToF32(const Packet8bf& a) {
EIGEN_STRONG_INLINE Packet8bf F32ToBf16(const Packet8f& a) {
Packet8bf r;
// Flush input denormals value to zero with hardware capability.
_MM_SET_DENORMALS_ZERO_MODE(_MM_DENORMALS_ZERO_ON);
__m256 flush = _mm256_and_ps(a, a);
_MM_SET_DENORMALS_ZERO_MODE(_MM_DENORMALS_ZERO_OFF);
__m256i input = _mm256_castps_si256(flush);
__m256i input = _mm256_castps_si256(a);
#ifdef EIGEN_VECTORIZE_AVX2
// uint32_t lsb = (input >> 16);
@@ -1293,7 +1288,7 @@ EIGEN_STRONG_INLINE Packet8bf F32ToBf16(const Packet8f& a) {
// input = input >> 16;
t = _mm256_srli_epi32(t, 16);
// Check NaN before converting back to bf16
__m256 mask = _mm256_cmp_ps(flush, flush, _CMP_ORD_Q);
__m256 mask = _mm256_cmp_ps(a, a, _CMP_ORD_Q);
__m256i nan = _mm256_set1_epi32(0x7fc0);
t = _mm256_blendv_epi8(nan, t, _mm256_castps_si256(mask));
// output = numext::bit_cast<uint16_t>(input);
@@ -1316,7 +1311,7 @@ EIGEN_STRONG_INLINE Packet8bf F32ToBf16(const Packet8f& a) {
lo = _mm_srli_epi32(lo, 16);
hi = _mm_srli_epi32(hi, 16);
// Check NaN before converting back to bf16
__m256 mask = _mm256_cmp_ps(flush, flush, _CMP_ORD_Q);
__m256 mask = _mm256_cmp_ps(a, a, _CMP_ORD_Q);
__m128i nan = _mm_set1_epi32(0x7fc0);
lo = _mm_blendv_epi8(nan, lo, _mm_castps_si128(_mm256_castps256_ps128(mask)));
hi = _mm_blendv_epi8(nan, hi, _mm_castps_si128(_mm256_extractf128_ps(mask, 1)));