From 0196141938e5f988308eab82450cf283dacdf844 Mon Sep 17 00:00:00 2001 From: Benoit Steiner Date: Mon, 2 Mar 2015 13:49:39 -0800 Subject: [PATCH] Fixed the optimized AVX implementation of the fast rsqrt function --- Eigen/src/Core/arch/AVX/MathFunctions.h | 30 ++++++++++++------------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/Eigen/src/Core/arch/AVX/MathFunctions.h b/Eigen/src/Core/arch/AVX/MathFunctions.h index 3031e7233..ef80a8b2d 100644 --- a/Eigen/src/Core/arch/AVX/MathFunctions.h +++ b/Eigen/src/Core/arch/AVX/MathFunctions.h @@ -312,31 +312,31 @@ Packet4d psqrt(const Packet4d& x) { #if EIGEN_FAST_MATH template<> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED -Packet4f prsqrt(const Packet4f& _x) { - _EIGEN_DECLARE_CONST_Packet4f_FROM_INT(inf, 0x7f800000); - _EIGEN_DECLARE_CONST_Packet4f_FROM_INT(nan, 0x7fc00000); - _EIGEN_DECLARE_CONST_Packet4f(one_point_five, 1.5f); - _EIGEN_DECLARE_CONST_Packet4f(minus_half, -0.5f); - _EIGEN_DECLARE_CONST_Packet4f_FROM_INT(flt_min, 0x00800000); +Packet8f prsqrt(const Packet8f& _x) { + _EIGEN_DECLARE_CONST_Packet8f_FROM_INT(inf, 0x7f800000); + _EIGEN_DECLARE_CONST_Packet8f_FROM_INT(nan, 0x7fc00000); + _EIGEN_DECLARE_CONST_Packet8f(one_point_five, 1.5f); + _EIGEN_DECLARE_CONST_Packet8f(minus_half, -0.5f); + _EIGEN_DECLARE_CONST_Packet8f_FROM_INT(flt_min, 0x00800000); - Packet4f neg_half = pmul(_x, p4f_minus_half); + Packet8f neg_half = pmul(_x, p8f_minus_half); // select only the inverse sqrt of positive normal inputs (denormals are // flushed to zero and cause infs as well). - Packet4f le_zero_mask = _mm_cmple_ps(_x, p4f_flt_min); - Packet4f x = _mm_andnot_ps(le_zero_mask, _mm_rsqrt_ps(_x)); + Packet8f le_zero_mask = _mm256_cmp_ps(_x, p8f_flt_min, _CMP_LT_OQ); + Packet8f x = _mm256_andnot_ps(le_zero_mask, _mm256_rsqrt_ps(_x)); // Fill in NaNs and Infs for the negative/zero entries. - Packet4f neg_mask = _mm_cmplt_ps(_x, _mm_setzero_ps()); - Packet4f zero_mask = _mm_andnot_ps(neg_mask, le_zero_mask); - Packet4f infs_and_nans = _mm_or_ps(_mm_and_ps(neg_mask, p4f_nan), - _mm_and_ps(zero_mask, p4f_inf)); + Packet8f neg_mask = _mm256_cmp_ps(_x, _mm256_setzero_ps(), _CMP_LT_OQ); + Packet8f zero_mask = _mm256_andnot_ps(neg_mask, le_zero_mask); + Packet8f infs_and_nans = _mm256_or_ps(_mm256_and_ps(neg_mask, p8f_nan), + _mm256_and_ps(zero_mask, p8f_inf)); // Do a single step of Newton's iteration. - x = pmul(x, pmadd(neg_half, pmul(x, x), p4f_one_point_five)); + x = pmul(x, pmadd(neg_half, pmul(x, x), p8f_one_point_five)); // Insert NaNs and Infs in all the right places. - return _mm_or_ps(x, infs_and_nans); + return _mm256_or_ps(x, infs_and_nans); } #else