[SelectionDAG] Unary vector constant folding integer legality fixes
This patch fixes issues with vector constant folding not correctly handling scalar input operands if they require implicit truncation - this was tested with llvm-stress as recommended by Patrik H Hagglund.
The patch ensures that integer input scalars from a build vector are correctly truncated before folding, and that constant integer scalar results are promoted to a legal type before inclusion in the new folded build vector.
I have added another crash test case and also a test for UINT_TO_FP / SINT_TO_FP using an non-truncated scalar input, which was failing before this patch.
Differential Revision: http://reviews.llvm.org/D9282
llvm-svn: 236308
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index d289406..9d403a6 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2858,23 +2858,43 @@
// FIXME: Entirely reasonable to perform folding of other unary
// operations here as the need arises.
break;
- case ISD::TRUNCATE:
- // Constant build vector truncation can be done with the original scalar
- // operands but with a new build vector with the truncated value type.
- return getNode(ISD::BUILD_VECTOR, DL, VT, BV->ops());
case ISD::FNEG:
case ISD::FABS:
case ISD::FCEIL:
case ISD::FTRUNC:
case ISD::FFLOOR:
case ISD::FP_EXTEND:
+ case ISD::TRUNCATE:
case ISD::UINT_TO_FP:
case ISD::SINT_TO_FP: {
+ EVT SVT = VT.getScalarType();
+ EVT InVT = BV->getValueType(0);
+ EVT InSVT = InVT.getScalarType();
+
+ // Find legal integer scalar type for constant promotion.
+ EVT LegalSVT = SVT;
+ if (SVT.isInteger()) {
+ LegalSVT = TLI->getTypeToTransformTo(*getContext(), SVT);
+ assert(LegalSVT.bitsGE(SVT) && "Unexpected legal scalar type size");
+ }
+
// Let the above scalar folding handle the folding of each element.
SmallVector<SDValue, 8> Ops;
for (int i = 0, e = VT.getVectorNumElements(); i != e; ++i) {
SDValue OpN = BV->getOperand(i);
- OpN = getNode(Opcode, DL, VT.getVectorElementType(), OpN);
+ EVT OpVT = OpN.getValueType();
+
+ // Build vector (integer) scalar operands may need implicit
+ // truncation - do this before constant folding.
+ if (OpVT.isInteger() && OpVT.bitsGT(InSVT))
+ OpN = getNode(ISD::TRUNCATE, DL, InSVT, OpN);
+
+ OpN = getNode(Opcode, DL, SVT, OpN);
+
+ // Legalize the (integer) scalar constant if necessary.
+ if (LegalSVT != SVT)
+ OpN = getNode(ISD::ANY_EXTEND, DL, LegalSVT, OpN);
+
if (OpN.getOpcode() != ISD::UNDEF &&
OpN.getOpcode() != ISD::Constant &&
OpN.getOpcode() != ISD::ConstantFP)