Enhance DAGCombine for transforming 128->256 casts into a vmovaps, rather
then a vxorps + vinsertf128 pair if the original vector came from a load.
rdar://10594409
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147481 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 08c09bd..47b80d0 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -12731,6 +12731,20 @@
!isUndefOrEqual(SVOp->getMaskElt(i+NumElems/2), NumElems))
return SDValue();
+ // If V1 is coming from a vector load then just fold to a VZEXT_LOAD.
+ if (LoadSDNode *Ld = dyn_cast<LoadSDNode>(V1.getOperand(0))) {
+ SDVTList Tys = DAG.getVTList(MVT::v4i64, MVT::Other);
+ SDValue Ops[] = { Ld->getChain(), Ld->getBasePtr() };
+ SDValue ResNode =
+ DAG.getMemIntrinsicNode(X86ISD::VZEXT_LOAD, dl, Tys, Ops, 2,
+ Ld->getMemoryVT(),
+ Ld->getPointerInfo(),
+ Ld->getAlignment(),
+ false/*isVolatile*/, true/*ReadMem*/,
+ false/*WriteMem*/);
+ return DAG.getNode(ISD::BITCAST, dl, VT, ResNode);
+ }
+
// Emit a zeroed vector and insert the desired subvector on its
// first half.
SDValue Zeros = getZeroVector(VT, true /* HasXMMInt */, DAG, dl);