diff options
| author |  Mark D Ryan <mark.d.ryan@intel.com> | 2018-07-30 13:21:00 +0200 |
|---|---|---|
| committer | Mark D Ryan <mark.d.ryan@intel.com> | 2018-07-30 13:21:00 +0200 |
| commit | bc615e458559480a95a6b6de32295b4aa646c72f (patch) | |
| tree | 0771ede7f217615dd25b6e6683c201d73052a1ed /Eigen/src/Core | |
| parent | 96b030a8e45a69d91fbd1f9ee1d9a48721f20e28 (diff) | |
Re-enable FMA for fast sqrt functions
Diffstat (limited to 'Eigen/src/Core')
| -rw-r--r-- | Eigen/src/Core/arch/AVX512/MathFunctions.h | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/Eigen/src/Core/arch/AVX512/MathFunctions.h b/Eigen/src/Core/arch/AVX512/MathFunctions.h index 81a3b4f62..ba1246722 100644 --- a/Eigen/src/Core/arch/AVX512/MathFunctions.h +++ b/Eigen/src/Core/arch/AVX512/MathFunctions.h @@ -258,7 +258,7 @@ pexp<Packet8d>(const Packet8d& _x) { template <> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED Packet16f psqrt<Packet16f>(const Packet16f& _x) { - Packet16f half = pmul(_x, pset1<Packet16f>(.5f)); + Packet16f neg_half = pmul(_x, pset1<Packet16f>(-.5f)); __mmask16 denormal_mask = _mm512_kand( _mm512_cmp_ps_mask(_x, pset1<Packet16f>((std::numeric_limits<float>::min)()), _CMP_LT_OQ), @@ -267,7 +267,7 @@ psqrt<Packet16f>(const Packet16f& _x) { Packet16f x = _mm512_rsqrt14_ps(_x); // Do a single step of Newton's iteration. - x = pmul(x, psub(pset1<Packet16f>(1.5f), pmul(half, pmul(x,x)))); + x = pmul(x, pmadd(neg_half, pmul(x, x), pset1<Packet16f>(1.5f))); // Flush results for denormals to zero. return _mm512_mask_blend_ps(denormal_mask, pmul(_x,x), _mm512_setzero_ps()); @@ -276,7 +276,7 @@ psqrt<Packet16f>(const Packet16f& _x) { template <> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED Packet8d psqrt<Packet8d>(const Packet8d& _x) { - Packet8d half = pmul(_x, pset1<Packet8d>(.5f)); + Packet8d neg_half = pmul(_x, pset1<Packet8d>(-.5f)); __mmask16 denormal_mask = _mm512_kand( _mm512_cmp_pd_mask(_x, pset1<Packet8d>((std::numeric_limits<double>::min)()), _CMP_LT_OQ), @@ -285,10 +285,10 @@ psqrt<Packet8d>(const Packet8d& _x) { Packet8d x = _mm512_rsqrt14_pd(_x); // Do a single step of Newton's iteration. - x = pmul(x, psub(pset1<Packet8d>(1.5f), pmul(half, pmul(x,x)))); + x = pmul(x, pmadd(neg_half, pmul(x, x), pset1<Packet8d>(1.5f))); // Do a second step of Newton's iteration. - x = pmul(x, psub(pset1<Packet8d>(1.5f), pmul(half, pmul(x,x)))); + x = pmul(x, pmadd(neg_half, pmul(x, x), pset1<Packet8d>(1.5f))); return _mm512_mask_blend_pd(denormal_mask, pmul(_x,x), _mm512_setzero_pd()); } |