[VectorLegalizer] ExpandANY_EXTEND_VECTOR_INREG/ExpandZERO_EXTEND_VECTOR_INREG - widen source vector

The *_EXTEND_VECTOR_INREG opcodes were relaxed back around rL346784 to support source vector widths that are smaller than the output - it looks like the legalizers were never updated to account for this.

This patch inserts the smaller source vector into an undef vector of the same width of the result before performing the shuffle+bitcast to correctly handle this.

Part of the yak shaving to solve the crashes from rL364264 and rL364272

llvm-svn: 364295

1 files changed, 26 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
index f77ccd994da..10b8b705869 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorOps.cpp
@@ -949,6 +949,19 @@ SDValue VectorLegalizer::ExpandANY_EXTEND_VECTOR_INREG(SDValue Op) {
   EVT SrcVT = Src.getValueType();
   int NumSrcElements = SrcVT.getVectorNumElements();
 
+  // *_EXTEND_VECTOR_INREG SrcVT can be smaller than VT - so insert the vector
+  // into a larger vector type.
+  if (SrcVT.bitsLE(VT)) {
+    assert((VT.getSizeInBits() % SrcVT.getScalarSizeInBits()) == 0 &&
+           "ANY_EXTEND_VECTOR_INREG vector size mismatch");
+    NumSrcElements = VT.getSizeInBits() / SrcVT.getScalarSizeInBits();
+    SrcVT = EVT::getVectorVT(*DAG.getContext(), SrcVT.getScalarType(),
+                             NumSrcElements);
+    Src = DAG.getNode(
+        ISD::INSERT_SUBVECTOR, DL, SrcVT, DAG.getUNDEF(SrcVT), Src,
+        DAG.getConstant(0, DL, TLI.getVectorIdxTy(DAG.getDataLayout())));
+  }
+
   // Build a base mask of undef shuffles.
   SmallVector<int, 16> ShuffleMask;
   ShuffleMask.resize(NumSrcElements, -1);
@@ -996,6 +1009,19 @@ SDValue VectorLegalizer::ExpandZERO_EXTEND_VECTOR_INREG(SDValue Op) {
   EVT SrcVT = Src.getValueType();
   int NumSrcElements = SrcVT.getVectorNumElements();
 
+  // *_EXTEND_VECTOR_INREG SrcVT can be smaller than VT - so insert the vector
+  // into a larger vector type.
+  if (SrcVT.bitsLE(VT)) {
+    assert((VT.getSizeInBits() % SrcVT.getScalarSizeInBits()) == 0 &&
+           "ZERO_EXTEND_VECTOR_INREG vector size mismatch");
+    NumSrcElements = VT.getSizeInBits() / SrcVT.getScalarSizeInBits();
+    SrcVT = EVT::getVectorVT(*DAG.getContext(), SrcVT.getScalarType(),
+                             NumSrcElements);
+    Src = DAG.getNode(
+        ISD::INSERT_SUBVECTOR, DL, SrcVT, DAG.getUNDEF(SrcVT), Src,
+        DAG.getConstant(0, DL, TLI.getVectorIdxTy(DAG.getDataLayout())));
+  }
+
   // Build up a zero vector to blend into this one.
   SDValue Zero = DAG.getConstant(0, DL, SrcVT);