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Fortify r152675 a bit. Although I'm not able to come up with a test case that would trigger the truncation case. 

llvm-svn: 152678
This commit is contained in:
Evan Cheng 2012-03-13 22:16:11 +00:00
parent 9ff686239a
commit d5f8e5766c
1 changed files with 11 additions and 3 deletions
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14
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -7204,7 +7204,7 @@ SDValue DAGCombiner::visitEXTRACT_VECTOR_ELT(SDNode *N) {
// If the result of load has to be truncated, then it's not necessarily
// profitable.
if (NVT.bitsLT(LVT))
if (NVT.bitsLT(LVT) && !TLI.isTruncateFree(LVT, NVT))
return SDValue();
if (InVec.getOpcode() == ISD::BITCAST) {
@ -7308,6 +7308,7 @@ SDValue DAGCombiner::visitEXTRACT_VECTOR_ELT(SDNode *N) {
// use of the load; that's okay because we don't want to perform this
// transformation in other cases anyway.
SDValue Load;
SDValue Chain;
if (NVT.bitsGT(LVT)) {
// If the result type of vextract is wider than the load, then issue an
// extending load instead.
@ -7316,14 +7317,21 @@ SDValue DAGCombiner::visitEXTRACT_VECTOR_ELT(SDNode *N) {
Load = DAG.getExtLoad(ExtType, N->getDebugLoc(), NVT, LN0->getChain(),
NewPtr, LN0->getPointerInfo().getWithOffset(PtrOff),
LVT, LN0->isVolatile(), LN0->isNonTemporal(),Align);
} else
Chain = Load.getValue(1);
} else {
Load = DAG.getLoad(LVT, N->getDebugLoc(), LN0->getChain(), NewPtr,
LN0->getPointerInfo().getWithOffset(PtrOff),
LN0->isVolatile(), LN0->isNonTemporal(),
LN0->isInvariant(), Align);
Chain = Load.getValue(1);
if (NVT.bitsLT(LVT))
Load = DAG.getNode(ISD::TRUNCATE, N->getDebugLoc(), NVT, Load);
else
Load = DAG.getNode(ISD::BITCAST, N->getDebugLoc(), NVT, Load);
}
WorkListRemover DeadNodes(*this);
SDValue From[] = { SDValue(N, 0), SDValue(LN0,1) };
SDValue To[] = { Load.getValue(0), Load.getValue(1) };
SDValue To[] = { Load, Chain };
DAG.ReplaceAllUsesOfValuesWith(From, To, 2, &DeadNodes);
// Since we're explcitly calling ReplaceAllUses, add the new node to the
// worklist explicitly as well.