[llvm] r327157 - [X86][SSE] createVariablePermute - move source vector canonicalization to top of function. NFCI.

[Simon Pilgrim via llvm-commits]

Author: rksimon
Date: Fri Mar  9 10:08:08 2018
New Revision: 327157

URL: http://llvm.org/viewvc/llvm-project?rev=327157&view=rev
Log:
[X86][SSE] createVariablePermute - move source vector canonicalization to top of function. NFCI.

This is to make it easier to return early from the switch statement with custom lowering.

Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=327157&r1=327156&r2=327157&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Fri Mar  9 10:08:08 2018
@@ -7926,6 +7926,14 @@ SDValue createVariablePermute(MVT VT, SD
                                   NumElts * VT.getScalarSizeInBits());
   IndicesVec = DAG.getZExtOrTrunc(IndicesVec, SDLoc(IndicesVec), IndicesVT);
 
+  // Adjust SrcVec to match VT type.
+  if (SrcVec.getValueSizeInBits() > VT.getSizeInBits())
+    return SDValue();
+  else if (SrcVec.getValueSizeInBits() < VT.getSizeInBits())
+    SrcVec =
+        DAG.getNode(ISD::INSERT_SUBVECTOR, SDLoc(SrcVec), VT, DAG.getUNDEF(VT),
+                    SrcVec, DAG.getIntPtrConstant(0, SDLoc(SrcVec)));
+
   unsigned Opcode = 0;
   switch (VT.SimpleTy) {
   default:
@@ -8004,14 +8012,6 @@ SDValue createVariablePermute(MVT VT, SD
          (VT.getScalarSizeInBits() % ShuffleVT.getScalarSizeInBits()) == 0 &&
          "Illegal variable permute shuffle type");
 
-  if (SrcVec.getValueSizeInBits() > VT.getSizeInBits())
-    return SDValue();
-  else if (SrcVec.getValueSizeInBits() < VT.getSizeInBits()) {
-    SrcVec =
-        DAG.getNode(ISD::INSERT_SUBVECTOR, SDLoc(SrcVec), VT, DAG.getUNDEF(VT),
-                    SrcVec, DAG.getIntPtrConstant(0, SDLoc(SrcVec)));
-  }
-
   uint64_t Scale = VT.getScalarSizeInBits() / ShuffleVT.getScalarSizeInBits();
   if (Scale > 1) {
     assert(isPowerOf2_64(Scale) && "Illegal variable permute shuffle scale");