From 6136f4fdd432dfff1c374348da8f76b9c93ac8ab Mon Sep 17 00:00:00 2001
From: Benoit Jacob <benoitjacob@google.com>
Date: Tue, 24 May 2016 10:00:32 -0400
Subject: [PATCH] Remove the rotating kernel. It was only useful on some ARM
 CPUs (Qualcomm Krait) that are not as ubiquitous today as they were when I
 introduced it.

---
 .../Core/products/GeneralBlockPanelKernel.h   | 100 +-----------------
 1 file changed, 5 insertions(+), 95 deletions(-)

diff --git a/Eigen/src/Core/products/GeneralBlockPanelKernel.h b/Eigen/src/Core/products/GeneralBlockPanelKernel.h
index e43529cc73..253c03462e 100644
--- a/Eigen/src/Core/products/GeneralBlockPanelKernel.h
+++ b/Eigen/src/Core/products/GeneralBlockPanelKernel.h
@@ -860,80 +860,6 @@ protected:
   conj_helper<ResPacket,ResPacket,false,ConjRhs> cj;
 };
 
-// helper for the rotating kernel below
-template <typename GebpKernel, bool UseRotatingKernel = GebpKernel::UseRotatingKernel>
-struct PossiblyRotatingKernelHelper
-{
-  // default implementation, not rotating
-
-  typedef typename GebpKernel::Traits Traits;
-  typedef typename Traits::RhsScalar RhsScalar;
-  typedef typename Traits::RhsPacket RhsPacket;
-  typedef typename Traits::AccPacket AccPacket;
-
-  const Traits& traits;
-  PossiblyRotatingKernelHelper(const Traits& t) : traits(t) {}
-
-
-  template <size_t K, size_t Index>
-  void loadOrRotateRhs(RhsPacket& to, const RhsScalar* from) const
-  {
-    traits.loadRhs(from + (Index+4*K)*Traits::RhsProgress, to);
-  }
-
-  void unrotateResult(AccPacket&,
-                      AccPacket&,
-                      AccPacket&,
-                      AccPacket&)
-  {
-  }
-};
-
-// rotating implementation
-template <typename GebpKernel>
-struct PossiblyRotatingKernelHelper<GebpKernel, true>
-{
-  typedef typename GebpKernel::Traits Traits;
-  typedef typename Traits::RhsScalar RhsScalar;
-  typedef typename Traits::RhsPacket RhsPacket;
-  typedef typename Traits::AccPacket AccPacket;
-
-  const Traits& traits;
-  PossiblyRotatingKernelHelper(const Traits& t) : traits(t) {}
-
-  template <size_t K, size_t Index>
-  void loadOrRotateRhs(RhsPacket& to, const RhsScalar* from) const
-  {
-    if (Index == 0) {
-      to = pload<RhsPacket>(from + 4*K*Traits::RhsProgress);
-    } else {
-      EIGEN_ASM_COMMENT("Do not reorder code, we're very tight on registers");
-      to = protate<1>(to);
-    }
-  }
-
-  void unrotateResult(AccPacket& res0,
-                      AccPacket& res1,
-                      AccPacket& res2,
-                      AccPacket& res3)
-  {
-    PacketBlock<AccPacket> resblock;
-    resblock.packet[0] = res0;
-    resblock.packet[1] = res1;
-    resblock.packet[2] = res2;
-    resblock.packet[3] = res3;
-    ptranspose(resblock);
-    resblock.packet[3] = protate<1>(resblock.packet[3]);
-    resblock.packet[2] = protate<2>(resblock.packet[2]);
-    resblock.packet[1] = protate<3>(resblock.packet[1]);
-    ptranspose(resblock);
-    res0 = resblock.packet[0];
-    res1 = resblock.packet[1];
-    res2 = resblock.packet[2];
-    res3 = resblock.packet[3];
-  }
-};
-
 /* optimized GEneral packed Block * packed Panel product kernel
  *
  * Mixing type logic: C += A * B
@@ -967,16 +893,6 @@ struct gebp_kernel
     ResPacketSize = Traits::ResPacketSize
   };
 
-
-  static const bool UseRotatingKernel =
-    EIGEN_ARCH_ARM &&
-    internal::is_same<LhsScalar, float>::value &&
-    internal::is_same<RhsScalar, float>::value &&
-    internal::is_same<ResScalar, float>::value &&
-    Traits::LhsPacketSize == 4 &&
-    Traits::RhsPacketSize == 4 &&
-    Traits::ResPacketSize == 4;
-
   EIGEN_DONT_INLINE
   void operator()(const DataMapper& res, const LhsScalar* blockA, const RhsScalar* blockB,
                   Index rows, Index depth, Index cols, ResScalar alpha,
@@ -1009,9 +925,7 @@ void gebp_kernel<LhsScalar,RhsScalar,Index,DataMapper,mr,nr,ConjugateLhs,Conjuga
     // This corresponds to 3*LhsProgress x nr register blocks.
     // Usually, make sense only with FMA
     if(mr>=3*Traits::LhsProgress)
-    {      
-      PossiblyRotatingKernelHelper<gebp_kernel> possiblyRotatingKernelHelper(traits);
-      
+    {
       // Here, the general idea is to loop on each largest micro horizontal panel of the lhs (3*Traits::LhsProgress x depth)
       // and on each largest micro vertical panel of the rhs (depth * nr).
       // Blocking sizes, i.e., 'depth' has been computed so that the micro horizontal panel of the lhs fit in L1.
@@ -1074,19 +988,19 @@ void gebp_kernel<LhsScalar,RhsScalar,Index,DataMapper,mr,nr,ConjugateLhs,Conjuga
               traits.loadLhs(&blA[(0+3*K)*LhsProgress], A0);  \
               traits.loadLhs(&blA[(1+3*K)*LhsProgress], A1);  \
               traits.loadLhs(&blA[(2+3*K)*LhsProgress], A2);  \
-              possiblyRotatingKernelHelper.template loadOrRotateRhs<K, 0>(B_0, blB); \
+              traits.loadRhs(blB + (0+4*K)*Traits::RhsProgress, B_0); \
               traits.madd(A0, B_0, C0, T0); \
               traits.madd(A1, B_0, C4, T0); \
               traits.madd(A2, B_0, C8, B_0); \
-              possiblyRotatingKernelHelper.template loadOrRotateRhs<K, 1>(B_0, blB); \
+              traits.loadRhs(blB + (1+4*K)*Traits::RhsProgress, B_0); \
               traits.madd(A0, B_0, C1, T0); \
               traits.madd(A1, B_0, C5, T0); \
               traits.madd(A2, B_0, C9, B_0); \
-              possiblyRotatingKernelHelper.template loadOrRotateRhs<K, 2>(B_0, blB); \
+              traits.loadRhs(blB + (2+4*K)*Traits::RhsProgress, B_0); \
               traits.madd(A0, B_0, C2,  T0); \
               traits.madd(A1, B_0, C6,  T0); \
               traits.madd(A2, B_0, C10, B_0); \
-              possiblyRotatingKernelHelper.template loadOrRotateRhs<K, 3>(B_0, blB); \
+              traits.loadRhs(blB + (3+4*K)*Traits::RhsProgress, B_0); \
               traits.madd(A0, B_0, C3 , T0); \
               traits.madd(A1, B_0, C7,  T0); \
               traits.madd(A2, B_0, C11, B_0); \
@@ -1120,10 +1034,6 @@ void gebp_kernel<LhsScalar,RhsScalar,Index,DataMapper,mr,nr,ConjugateLhs,Conjuga
 
 #undef EIGEN_GEBP_ONESTEP
 
-          possiblyRotatingKernelHelper.unrotateResult(C0, C1, C2, C3);
-          possiblyRotatingKernelHelper.unrotateResult(C4, C5, C6, C7);
-          possiblyRotatingKernelHelper.unrotateResult(C8, C9, C10, C11);
-
           ResPacket R0, R1, R2;
           ResPacket alphav = pset1<ResPacket>(alpha);