[DAGCombiner] Avoid introducing an illegal build_vector when folding a sign_extend.
Make sure that we don't introduce illegal build_vector dag nodes
when trying to fold a sign_extend of a build_vector.
This fixes a regression introduced by r200234.
Added test CodeGen/X86/fold-vector-sext-crash.ll
to verify that llc no longer crashes with an assertion failure
due to an illegal build_vector of type MVT::v4i64.
Thanks to Ilia Filippov for spotting this regression and for
providing a reproducible test case.
llvm-svn: 200313
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 1b0b2ef..e96a7aa 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -4583,7 +4583,8 @@
// dag nodes (see for example method DAGCombiner::visitSIGN_EXTEND).
// Vector extends are not folded if operations are legal; this is to
// avoid introducing illegal build_vector dag nodes.
-static SDNode *tryToFoldExtendOfConstant(SDNode *N, SelectionDAG &DAG,
+static SDNode *tryToFoldExtendOfConstant(SDNode *N, const TargetLowering &TLI,
+ SelectionDAG &DAG, bool LegalTypes,
bool LegalOperations) {
unsigned Opcode = N->getOpcode();
SDValue N0 = N->getOperand(0);
@@ -4601,12 +4602,14 @@
// fold (sext (build_vector AllConstants) -> (build_vector AllConstants)
// fold (zext (build_vector AllConstants) -> (build_vector AllConstants)
// fold (aext (build_vector AllConstants) -> (build_vector AllConstants)
- if (!(VT.isVector() && !LegalOperations &&
+ EVT SVT = VT.getScalarType();
+ if (!(VT.isVector() &&
+ (!LegalTypes || (!LegalOperations && TLI.isTypeLegal(SVT))) &&
ISD::isBuildVectorOfConstantSDNodes(N0.getNode())))
return 0;
// We can fold this node into a build_vector.
- unsigned VTBits = VT.getScalarType().getSizeInBits();
+ unsigned VTBits = SVT.getSizeInBits();
unsigned EVTBits = N0->getValueType(0).getScalarType().getSizeInBits();
unsigned ShAmt = VTBits - EVTBits;
SmallVector<SDValue, 8> Elts;
@@ -4616,7 +4619,7 @@
for (unsigned i=0; i != NumElts; ++i) {
SDValue Op = N0->getOperand(i);
if (Op->getOpcode() == ISD::UNDEF) {
- Elts.push_back(DAG.getUNDEF(VT.getScalarType()));
+ Elts.push_back(DAG.getUNDEF(SVT));
continue;
}
@@ -4624,10 +4627,10 @@
const APInt &C = APInt(VTBits, CurrentND->getAPIntValue().getZExtValue());
if (Opcode == ISD::SIGN_EXTEND)
Elts.push_back(DAG.getConstant(C.shl(ShAmt).ashr(ShAmt).getZExtValue(),
- VT.getScalarType()));
+ SVT));
else
Elts.push_back(DAG.getConstant(C.shl(ShAmt).lshr(ShAmt).getZExtValue(),
- VT.getScalarType()));
+ SVT));
}
return DAG.getNode(ISD::BUILD_VECTOR, DL, VT, &Elts[0], NumElts).getNode();
@@ -4723,7 +4726,8 @@
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
- if (SDNode *Res = tryToFoldExtendOfConstant(N, DAG, LegalOperations))
+ if (SDNode *Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes,
+ LegalOperations))
return SDValue(Res, 0);
// fold (sext (sext x)) -> (sext x)
@@ -4978,7 +4982,8 @@
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
- if (SDNode *Res = tryToFoldExtendOfConstant(N, DAG, LegalOperations))
+ if (SDNode *Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes,
+ LegalOperations))
return SDValue(Res, 0);
// fold (zext (zext x)) -> (zext x)
@@ -5247,7 +5252,8 @@
SDValue N0 = N->getOperand(0);
EVT VT = N->getValueType(0);
- if (SDNode *Res = tryToFoldExtendOfConstant(N, DAG, LegalOperations))
+ if (SDNode *Res = tryToFoldExtendOfConstant(N, TLI, DAG, LegalTypes,
+ LegalOperations))
return SDValue(Res, 0);
// fold (aext (aext x)) -> (aext x)