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Reapply 154397. Original message: 

Fix a dagcombine optimization which assumes that the vsetcc result type is always
of the same size as the compared values. This is ture for SSE/AVX/NEON but not
for all targets.

llvm-svn: 154490
This commit is contained in:
Nadav Rotem 2012-04-11 08:26:11 +00:00
parent a4b125634e
commit 9d376b6578
1 changed files with 18 additions and 11 deletions
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29
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -4354,12 +4354,17 @@ SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
// Only do this before legalize for now.
if (VT.isVector() && !LegalOperations) {
EVT N0VT = N0.getOperand(0).getValueType();
// We know that the # elements of the results is the same as the
// # elements of the compare (and the # elements of the compare result
// for that matter). Check to see that they are the same size. If so,
// we know that the element size of the sext'd result matches the
// element size of the compare operands.
if (VT.getSizeInBits() == N0VT.getSizeInBits())
// On some architectures (such as SSE/NEON/etc) the SETCC result type is
// of the same size as the compared operands. Only optimize sext(setcc())
// if this is the case.
EVT SVT = TLI.getSetCCResultType(N0VT);
// We know that the # elements of the results is the same as the
// # elements of the compare (and the # elements of the compare result
// for that matter). Check to see that they are the same size. If so,
// we know that the element size of the sext'd result matches the
// element size of the compare operands.
if (VT.getSizeInBits() == SVT.getSizeInBits())
return DAG.getSetCC(N->getDebugLoc(), VT, N0.getOperand(0),
N0.getOperand(1),
cast<CondCodeSDNode>(N0.getOperand(2))->get());
@ -4373,11 +4378,13 @@ SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
EVT MatchingVectorType =
EVT::getVectorVT(*DAG.getContext(), MatchingElementType,
N0VT.getVectorNumElements());
SDValue VsetCC =
DAG.getSetCC(N->getDebugLoc(), MatchingVectorType, N0.getOperand(0),
N0.getOperand(1),
cast<CondCodeSDNode>(N0.getOperand(2))->get());
return DAG.getSExtOrTrunc(VsetCC, N->getDebugLoc(), VT);
if (SVT == MatchingVectorType) {
SDValue VsetCC = DAG.getSetCC(N->getDebugLoc(), MatchingVectorType,
N0.getOperand(0), N0.getOperand(1),
cast<CondCodeSDNode>(N0.getOperand(2))->get());
return DAG.getSExtOrTrunc(VsetCC, N->getDebugLoc(), VT);
}
}
}