commit b4f31dd1a8a4aa9b8fa36e654a05c13862916bb4
author Evan Cheng <evan.cheng@apple.com> Sun Apr 23 06:35:19 2006 +0000
committer Evan Cheng <evan.cheng@apple.com> Sun Apr 23 06:35:19 2006 +0000
tree 9458c041648fbf24c1008bf75970f5de2b42c14c
parent 866b4b4d458caa9d9d7efccc688868c532553b68

MOVL shuffle (i.e. movd or movss / movsd from memory) of undef, V2 == V2

llvm-svn: 27953

llvm/lib/Target/X86/X86ISelLowering.cpp

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 3861fc3..8d52c56 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -2973,6 +2973,8 @@
     SDOperand PermMask = Op.getOperand(2);
     MVT::ValueType VT = Op.getValueType();
     unsigned NumElems = PermMask.getNumOperands();
+    bool V1IsUndef = V1.getOpcode() == ISD::UNDEF;
+    bool V2IsUndef = V2.getOpcode() == ISD::UNDEF;
 
     if (isSplatMask(PermMask.Val)) {
       if (NumElems <= 4) return Op;
@@ -2980,8 +2982,10 @@
       return PromoteSplat(Op, DAG);
     }
 
-    if (X86::isMOVLMask(PermMask.Val) ||
-        X86::isMOVSHDUPMask(PermMask.Val) ||
+    if (X86::isMOVLMask(PermMask.Val))
+      return (V1IsUndef) ? V2 : Op;
+      
+    if (X86::isMOVSHDUPMask(PermMask.Val) ||
         X86::isMOVSLDUPMask(PermMask.Val) ||
         X86::isMOVHLPSMask(PermMask.Val) ||
         X86::isMOVHPMask(PermMask.Val) ||
@@ -3003,6 +3007,7 @@
     }
 
     if (isCommutedMOVL(PermMask.Val, V2IsSplat)) {
+      if (V2IsUndef) return V1;
       Op = CommuteVectorShuffle(Op, DAG);
       V1 = Op.getOperand(0);
       V2 = Op.getOperand(1);