[Hexagon] Make floating point operations expensive for vectorization

llvm-svn: 334508

2 files changed, 35 insertions, 6 deletions

diff --git a/llvm/lib/Target/Hexagon/HexagonTargetTransformInfo.cpp b/llvm/lib/Target/Hexagon/HexagonTargetTransformInfo.cpp
index bca856ae9cb..a496a17788d 100644
--- a/llvm/lib/Target/Hexagon/HexagonTargetTransformInfo.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonTargetTransformInfo.cpp
@@ -35,6 +35,10 @@ static cl::opt<bool> EmitLookupTables("hexagon-emit-lookup-tables",
   cl::init(true), cl::Hidden,
   cl::desc("Control lookup table emission on Hexagon target"));
 
+// Constant "cost factor" to make floating point operations more expensive
+// in terms of vectorization cost. This isn't the best way, but it should
+// do. Ultimately, the cost should use cycles.
+static const unsigned FloatFactor = 4;
 
 bool HexagonTTIImpl::useHVX() const {
   return ST.useHVXOps() && HexagonAutoHVX;
@@ -54,6 +58,14 @@ bool HexagonTTIImpl::isTypeForHVX(Type *VecTy) const {
   return Action == TargetLoweringBase::TypeWidenVector;
 }
 
+unsigned HexagonTTIImpl::getTypeNumElements(Type *Ty) const {
+  if (Ty->isVectorTy())
+    return Ty->getVectorNumElements();
+  assert((Ty->isIntegerTy() || Ty->isFloatingPointTy()) &&
+         "Expecting scalar type");
+  return 1;
+}
+
 TargetTransformInfo::PopcntSupportKind
 HexagonTTIImpl::getPopcntSupport(unsigned IntTyWidthInBit) const {
   // Return fast hardware support as every input < 64 bits will be promoted
@@ -161,8 +173,8 @@ unsigned HexagonTTIImpl::getMemoryOpCost(unsigned Opcode, Type *Src,
 
     // Non-HVX vectors.
     // Add extra cost for floating point types.
-    unsigned Cost = VecTy->getElementType()->isFloatingPointTy() ? 4 : 1;
-
+    unsigned Cost = VecTy->getElementType()->isFloatingPointTy() ? FloatFactor
+                                                                 : 1;
     Alignment = std::min(Alignment, 8u);
     unsigned AlignWidth = 8 * std::max(1u, Alignment);
     unsigned NumLoads = alignTo(VecWidth, AlignWidth) / AlignWidth;
@@ -202,10 +214,9 @@ unsigned HexagonTTIImpl::getInterleavedMemoryOpCost(unsigned Opcode,
 unsigned HexagonTTIImpl::getCmpSelInstrCost(unsigned Opcode, Type *ValTy,
       Type *CondTy, const Instruction *I) {
   if (ValTy->isVectorTy()) {
-    auto *VecTy = dyn_cast<VectorType>(ValTy);
     std::pair<int, MVT> LT = TLI.getTypeLegalizationCost(DL, ValTy);
     if (Opcode == Instruction::FCmp)
-      return LT.first + 4 * VecTy->getNumElements();
+      return LT.first + FloatFactor * getTypeNumElements(ValTy);
   }
   return BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, I);
 }
@@ -214,12 +225,25 @@ unsigned HexagonTTIImpl::getArithmeticInstrCost(unsigned Opcode, Type *Ty,
       TTI::OperandValueKind Opd1Info, TTI::OperandValueKind Opd2Info,
       TTI::OperandValueProperties Opd1PropInfo,
       TTI::OperandValueProperties Opd2PropInfo, ArrayRef<const Value*> Args) {
+  if (Ty->isVectorTy()) {
+    std::pair<int, MVT> LT = TLI.getTypeLegalizationCost(DL, Ty);
+    if (LT.second.isFloatingPoint())
+      return LT.first + FloatFactor * getTypeNumElements(Ty);
+  }
   return BaseT::getArithmeticInstrCost(Opcode, Ty, Opd1Info, Opd2Info,
                                        Opd1PropInfo, Opd2PropInfo, Args);
 }
 
-unsigned HexagonTTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst,
-      Type *Src, const Instruction *I) {
+unsigned HexagonTTIImpl::getCastInstrCost(unsigned Opcode, Type *DstTy,
+      Type *SrcTy, const Instruction *I) {
+  if (SrcTy->isFPOrFPVectorTy() || DstTy->isFPOrFPVectorTy()) {
+    unsigned SrcN = SrcTy->isFPOrFPVectorTy() ? getTypeNumElements(SrcTy) : 0;
+    unsigned DstN = DstTy->isFPOrFPVectorTy() ? getTypeNumElements(DstTy) : 0;
+
+    std::pair<int, MVT> SrcLT = TLI.getTypeLegalizationCost(DL, SrcTy);
+    std::pair<int, MVT> DstLT = TLI.getTypeLegalizationCost(DL, DstTy);
+    return std::max(SrcLT.first, DstLT.first) + FloatFactor * (SrcN + DstN);
+  }
   return 1;
 }
 
diff --git a/llvm/lib/Target/Hexagon/HexagonTargetTransformInfo.h b/llvm/lib/Target/Hexagon/HexagonTargetTransformInfo.h
index 99de5c017e2..a232f99fc40 100644
--- a/llvm/lib/Target/Hexagon/HexagonTargetTransformInfo.h
+++ b/llvm/lib/Target/Hexagon/HexagonTargetTransformInfo.h
@@ -46,6 +46,11 @@ class HexagonTTIImpl : public BasicTTIImplBase<HexagonTTIImpl> {
   bool useHVX() const;
   bool isTypeForHVX(Type *VecTy) const;
 
+  // Returns the number of vector elements of Ty, if Ty is a vector type,
+  // or 1 if Ty is a scalar type. It is incorrect to call this function
+  // with any other type.
+  unsigned getTypeNumElements(Type *Ty) const;
+
 public:
   explicit HexagonTTIImpl(const HexagonTargetMachine *TM, const Function &F)
       : BaseT(TM, F.getParent()->getDataLayout()),