Don't try to make BUILD_VECTOR operands have the same

type as the vector element type: allow them to be of
a wider integer type than the element type all the way
through the system, and not just as far as LegalizeDAG.
This should be safe because it used to be this way
(the old type legalizer would produce such nodes), so
backends should be able to handle it.  In fact only
targets which have legal vector types with an illegal
promoted element type will ever see this (eg: <4 x i16>
on ppc).  This fixes a regression with the new type
legalizer (vec_splat.ll).  Also, treat SCALAR_TO_VECTOR
the same as BUILD_VECTOR.  After all, it is just a
special case of BUILD_VECTOR.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@69467 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 2 deletions

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index dd4fda1e84..d1ef0815c8 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -5110,8 +5110,15 @@ SDValue DAGCombiner::visitEXTRACT_VECTOR_ELT(SDNode *N) {
   // (vextract (scalar_to_vector val, 0) -> val
   SDValue InVec = N->getOperand(0);
 
- if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR)
-   return InVec.getOperand(0);
+ if (InVec.getOpcode() == ISD::SCALAR_TO_VECTOR) {
+   // If the operand is wider than the vector element type then it is implicitly
+   // truncated.  Make that explicit here.
+   MVT EltVT = InVec.getValueType().getVectorElementType();
+   SDValue InOp = InVec.getOperand(0);
+   if (InOp.getValueType() != EltVT)
+     return DAG.getNode(ISD::TRUNCATE, InVec.getDebugLoc(), EltVT, InOp);
+   return InOp;
+ }
 
   // Perform only after legalization to ensure build_vector / vector_shuffle
   // optimizations have already been done.