Don't emit SAR X, 0 in the case of sdiv Y, 2
llvm-svn: 21986
diff --git a/llvm/lib/Target/X86/X86ISelPattern.cpp b/llvm/lib/Target/X86/X86ISelPattern.cpp
index fcea635..ba36443 100644
--- a/llvm/lib/Target/X86/X86ISelPattern.cpp
+++ b/llvm/lib/Target/X86/X86ISelPattern.cpp
@@ -2699,8 +2699,13 @@
}
unsigned RegSize = MVT::getSizeInBits(N.getValueType());
Tmp1 = SelectExpr(N.getOperand(0));
- unsigned TmpReg = MakeReg(N.getValueType());
- BuildMI(BB, SAROpc, 2, TmpReg).addReg(Tmp1).addImm(Log-1);
+ unsigned TmpReg;
+ if (Log != 1) {
+ TmpReg = MakeReg(N.getValueType());
+ BuildMI(BB, SAROpc, 2, TmpReg).addReg(Tmp1).addImm(Log-1);
+ } else {
+ TmpReg = Tmp1;
+ }
unsigned TmpReg2 = MakeReg(N.getValueType());
BuildMI(BB, SHROpc, 2, TmpReg2).addReg(TmpReg).addImm(RegSize-Log);
unsigned TmpReg3 = MakeReg(N.getValueType());