fix NEON port, use vget_lane_*() instead of temporary variables (saves extra

load/store), following advice by  Josh Bleecher Snyder <josharian@gmail.com>.
Also implement pmadd() using vmla instead of nested padd/pmul.

1 files changed, 11 insertions, 27 deletions

diff --git a/Eigen/src/Core/arch/NEON/PacketMath.h b/Eigen/src/Core/arch/NEON/PacketMath.h
index 1eb082a5b..90dd335a1 100644
--- a/Eigen/src/Core/arch/NEON/PacketMath.h
+++ b/Eigen/src/Core/arch/NEON/PacketMath.h
@@ -252,15 +252,12 @@ template<> EIGEN_STRONG_INLINE Packet4i pabs(const Packet4i& a) { return vabsq_s
 template<> EIGEN_STRONG_INLINE float predux<Packet4f>(const Packet4f& a)
 {
   float32x2_t a_lo, a_hi, sum;
-  float s[2];
 
   a_lo = vget_low_f32(a);
   a_hi = vget_high_f32(a);
   sum = vpadd_f32(a_lo, a_hi);
   sum = vpadd_f32(sum, sum);
-  vst1_f32(s, sum);
-
-  return s[0];
+  return vget_lane_f32(sum, 0);
 }
 
 template<> EIGEN_STRONG_INLINE Packet4f preduxp<Packet4f>(const Packet4f* vecs)
@@ -286,15 +283,12 @@ template<> EIGEN_STRONG_INLINE Packet4f preduxp<Packet4f>(const Packet4f* vecs)
 template<> EIGEN_STRONG_INLINE int predux<Packet4i>(const Packet4i& a)
 {
   int32x2_t a_lo, a_hi, sum;
-  int32_t s[2];
 
   a_lo = vget_low_s32(a);
   a_hi = vget_high_s32(a);
   sum = vpadd_s32(a_lo, a_hi);
   sum = vpadd_s32(sum, sum);
-  vst1_s32(s, sum);
-
-  return s[0];
+  return vget_lane_s32(sum, 0);
 }
 
 template<> EIGEN_STRONG_INLINE Packet4i preduxp<Packet4i>(const Packet4i* vecs)
@@ -322,7 +316,6 @@ template<> EIGEN_STRONG_INLINE Packet4i preduxp<Packet4i>(const Packet4i* vecs)
 template<> EIGEN_STRONG_INLINE float predux_mul<Packet4f>(const Packet4f& a)
 {
   float32x2_t a_lo, a_hi, prod;
-  float s[2];
 
   // Get a_lo = |a1|a2| and a_hi = |a3|a4|
   a_lo = vget_low_f32(a);
@@ -331,14 +324,12 @@ template<> EIGEN_STRONG_INLINE float predux_mul<Packet4f>(const Packet4f& a)
   prod = vmul_f32(a_lo, a_hi);
   // Multiply prod with its swapped value |a2*a4|a1*a3|
   prod = vmul_f32(prod, vrev64_f32(prod));
-  vst1_f32(s, prod);
 
-  return s[0];
+  return vget_lane_f32(prod, 0);
 }
 template<> EIGEN_STRONG_INLINE int predux_mul<Packet4i>(const Packet4i& a)
 {
   int32x2_t a_lo, a_hi, prod;
-  int32_t s[2];
 
   // Get a_lo = |a1|a2| and a_hi = |a3|a4|
   a_lo = vget_low_s32(a);
@@ -347,65 +338,58 @@ template<> EIGEN_STRONG_INLINE int predux_mul<Packet4i>(const Packet4i& a)
   prod = vmul_s32(a_lo, a_hi);
   // Multiply prod with its swapped value |a2*a4|a1*a3|
   prod = vmul_s32(prod, vrev64_s32(prod));
-  vst1_s32(s, prod);
 
-  return s[0];
+  return vget_lane_s32(prod, 0);
 }
 
 // min
 template<> EIGEN_STRONG_INLINE float predux_min<Packet4f>(const Packet4f& a)
 {
   float32x2_t a_lo, a_hi, min;
-  float s[2];
 
   a_lo = vget_low_f32(a);
   a_hi = vget_high_f32(a);
   min = vpmin_f32(a_lo, a_hi);
   min = vpmin_f32(min, min);
-  vst1_f32(s, min);
 
-  return s[0];
+  return vget_lane_f32(min, 0);
 }
+
 template<> EIGEN_STRONG_INLINE int predux_min<Packet4i>(const Packet4i& a)
 {
   int32x2_t a_lo, a_hi, min;
-  int32_t s[2];
 
   a_lo = vget_low_s32(a);
   a_hi = vget_high_s32(a);
   min = vpmin_s32(a_lo, a_hi);
   min = vpmin_s32(min, min);
   vst1_s32(s, min);
-
-  return s[0];
+  
+  return vget_lane_s32(min, 0);
 }
 
 // max
 template<> EIGEN_STRONG_INLINE float predux_max<Packet4f>(const Packet4f& a)
 {
   float32x2_t a_lo, a_hi, max;
-  float s[2];
 
   a_lo = vget_low_f32(a);
   a_hi = vget_high_f32(a);
   max = vpmax_f32(a_lo, a_hi);
   max = vpmax_f32(max, max);
-  vst1_f32(s, max);
 
-  return s[0];
+  return vget_lane_s32(max, 0);
 }
+
 template<> EIGEN_STRONG_INLINE int predux_max<Packet4i>(const Packet4i& a)
 {
   int32x2_t a_lo, a_hi, max;
-  int32_t s[2];
 
   a_lo = vget_low_s32(a);
   a_hi = vget_high_s32(a);
   max = vpmax_s32(a_lo, a_hi);
-  max = vpmax_s32(max, max);
-  vst1_s32(s, max);
 
-  return s[0];
+  return vget_lane_s32(max, 0);
 }
 
 // this PALIGN_NEON business is to work around a bug in LLVM Clang 3.0 causing incorrect compilation errors,