Don't insert 128-bit UNDEF into 256-bit vectors. Just keep the 256-bit vector. Original patch by Elena Demikhovsky. Tweaked by me to allow possibility of covering more cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158792 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index dec8d07..2576821 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -99,6 +99,10 @@
static SDValue Insert128BitVector(SDValue Result, SDValue Vec,
unsigned IdxVal, SelectionDAG &DAG,
DebugLoc dl) {
+ // Inserting UNDEF is Result
+ if (Vec.getOpcode() == ISD::UNDEF)
+ return Result;
+
EVT VT = Vec.getValueType();
assert(VT.getSizeInBits() == 128 && "Unexpected vector size!");
@@ -114,9 +118,8 @@
* ElemsPerChunk);
SDValue VecIdx = DAG.getConstant(NormalizedIdxVal, MVT::i32);
- Result = DAG.getNode(ISD::INSERT_SUBVECTOR, dl, ResultVT, Result, Vec,
- VecIdx);
- return Result;
+ return DAG.getNode(ISD::INSERT_SUBVECTOR, dl, ResultVT, Result, Vec,
+ VecIdx);
}
/// Concat two 128-bit vectors into a 256 bit vector using VINSERTF128