Cost Model: Move the 'max unroll factor' variable to the TTI and add initial Cost Model support on ARM.

llvm-svn: 171928

1 files changed, 13 insertions, 2 deletions

diff --git a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
index 9cc1b180e97..6ab08cbd129 100644
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -75,7 +75,6 @@ public:
 
   /// \name Scalar TTI Implementations
   /// @{
-
   virtual PopcntSupportKind getPopcntSupport(unsigned TyWidth) const;
 
   /// @}
@@ -84,6 +83,7 @@ public:
   /// @{
 
   virtual unsigned getNumberOfRegisters(bool Vector) const;
+  virtual unsigned getMaximumUnrollFactor() const;
   virtual unsigned getArithmeticInstrCost(unsigned Opcode, Type *Ty) const;
   virtual unsigned getShuffleCost(ShuffleKind Kind, Type *Tp,
                                   int Index, Type *SubTp) const;
@@ -156,7 +156,6 @@ FindInConvertTable(const X86TypeConversionCostTblEntry *Tbl, unsigned len,
   return -1;
 }
 
-
 X86TTI::PopcntSupportKind X86TTI::getPopcntSupport(unsigned TyWidth) const {
   assert(isPowerOf2_32(TyWidth) && "Ty width must be power of 2");
   // TODO: Currently the __builtin_popcount() implementation using SSE3
@@ -171,6 +170,18 @@ unsigned X86TTI::getNumberOfRegisters(bool Vector) const {
   return 8;
 }
 
+unsigned X86TTI::getMaximumUnrollFactor() const {
+  if (ST->isAtom())
+    return 1;
+
+  // Sandybridge and Haswell have multiple execution ports and pipelined
+  // vector units.
+  if (ST->hasAVX())
+    return 4;
+
+  return 2;
+}
+
 unsigned X86TTI::getArithmeticInstrCost(unsigned Opcode, Type *Ty) const {
   // Legalize the type.
   std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Ty);