[X86] Never hoist the shift value of a shift instruction.

There is no need to check if we want to hoist the immediate value of an
shift instruction. Simply return TCC_Free right away.

This change is like r206101, but for X86.

rdar://problem/16190769

llvm-svn: 207692

1 files changed, 7 insertions, 3 deletions

diff --git a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
index 1543f109b4c..ce060aba644 100644
--- a/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
+++ b/llvm/lib/Target/X86/X86TargetTransformInfo.cpp
@@ -956,15 +956,19 @@ unsigned X86TTI::getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm,
   case Instruction::SDiv:
   case Instruction::URem:
   case Instruction::SRem:
-  case Instruction::Shl:
-  case Instruction::LShr:
-  case Instruction::AShr:
   case Instruction::And:
   case Instruction::Or:
   case Instruction::Xor:
   case Instruction::ICmp:
     ImmIdx = 1;
     break;
+  // Always return TCC_Free for the shift value of a shift instruction.
+  case Instruction::Shl:
+  case Instruction::LShr:
+  case Instruction::AShr:
+    if (Idx == 1)
+      return TCC_Free;
+    break;
   case Instruction::Trunc:
   case Instruction::ZExt:
   case Instruction::SExt: