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- When legal, promote a load to zextload rather than ext load. 

- Catch more further dag combine opportunities as result of operand promotion, e.g. (i32 anyext (i16 trunc (i32 x))) -> (i32 x)

llvm-svn: 102455
This commit is contained in:
Evan Cheng 2010-04-27 19:48:13 +00:00
parent 6c74a872a8
commit e813690b7a
1 changed files with 20 additions and 6 deletions
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26
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -656,19 +656,22 @@ void DAGCombiner::ReplaceLoadWithPromotedLoad(SDNode *Load, SDNode *ExtLoad) {
&DeadNodes);
removeFromWorkList(Load);
DAG.DeleteNode(Load);
AddToWorkList(Trunc.getNode());
}
SDValue DAGCombiner::PromoteOperand(SDValue Op, EVT PVT, bool &Replace) {
Replace = false;
DebugLoc dl = Op.getDebugLoc();
if (LoadSDNode *LD = dyn_cast<LoadSDNode>(Op)) {
ISD::LoadExtType ExtType =
ISD::isNON_EXTLoad(LD) ? ISD::EXTLOAD : LD->getExtensionType();
EVT MemVT = LD->getMemoryVT();
ISD::LoadExtType ExtType = ISD::isNON_EXTLoad(LD)
? (TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT) ? ISD::ZEXTLOAD : ISD::EXTLOAD)
: LD->getExtensionType();
Replace = true;
return DAG.getExtLoad(ExtType, dl, PVT,
LD->getChain(), LD->getBasePtr(),
LD->getSrcValue(), LD->getSrcValueOffset(),
LD->getMemoryVT(), LD->isVolatile(),
MemVT, LD->isVolatile(),
LD->isNonTemporal(), LD->getAlignment());
}
@ -704,6 +707,7 @@ SDValue DAGCombiner::SExtPromoteOperand(SDValue Op, EVT PVT) {
SDValue NewOp = PromoteOperand(Op, PVT, Replace);
if (NewOp.getNode() == 0)
return SDValue();
AddToWorkList(NewOp.getNode());
if (Replace)
ReplaceLoadWithPromotedLoad(Op.getNode(), NewOp.getNode());
@ -718,6 +722,7 @@ SDValue DAGCombiner::ZExtPromoteOperand(SDValue Op, EVT PVT) {
SDValue NewOp = PromoteOperand(Op, PVT, Replace);
if (NewOp.getNode() == 0)
return SDValue();
AddToWorkList(NewOp.getNode());
if (Replace)
ReplaceLoadWithPromotedLoad(Op.getNode(), NewOp.getNode());
@ -767,6 +772,8 @@ SDValue DAGCombiner::PromoteIntBinOp(SDValue Op) {
if (Replace1)
ReplaceLoadWithPromotedLoad(N1.getNode(), NN1.getNode());
DEBUG(dbgs() << "\nPromoting ";
Op.getNode()->dump(&DAG));
DebugLoc dl = Op.getDebugLoc();
return DAG.getNode(ISD::TRUNCATE, dl, VT,
DAG.getNode(Opc, dl, PVT, NN0, NN1));
@ -812,6 +819,8 @@ SDValue DAGCombiner::PromoteIntShiftOp(SDValue Op) {
if (Replace)
ReplaceLoadWithPromotedLoad(Op.getOperand(0).getNode(), N0.getNode());
DEBUG(dbgs() << "\nPromoting ";
Op.getNode()->dump(&DAG));
DebugLoc dl = Op.getDebugLoc();
return DAG.getNode(ISD::TRUNCATE, dl, VT,
DAG.getNode(Opc, dl, PVT, N0, Op.getOperand(1)));
@ -841,6 +850,8 @@ SDValue DAGCombiner::PromoteExtend(SDValue Op) {
// fold (aext (aext x)) -> (aext x)
// fold (aext (zext x)) -> (zext x)
// fold (aext (sext x)) -> (sext x)
DEBUG(dbgs() << "\nPromoting ";
Op.getNode()->dump(&DAG));
return DAG.getNode(Op.getOpcode(), Op.getDebugLoc(), VT, Op.getOperand(0));
}
return SDValue();
@ -869,12 +880,14 @@ bool DAGCombiner::PromoteLoad(SDValue Op) {
DebugLoc dl = Op.getDebugLoc();
SDNode *N = Op.getNode();
LoadSDNode *LD = cast<LoadSDNode>(N);
ISD::LoadExtType ExtType =
ISD::isNON_EXTLoad(LD) ? ISD::EXTLOAD : LD->getExtensionType();
EVT MemVT = LD->getMemoryVT();
ISD::LoadExtType ExtType = ISD::isNON_EXTLoad(LD)
? (TLI.isLoadExtLegal(ISD::ZEXTLOAD, MemVT) ? ISD::ZEXTLOAD : ISD::EXTLOAD)
: LD->getExtensionType();
SDValue NewLD = DAG.getExtLoad(ExtType, dl, PVT,
LD->getChain(), LD->getBasePtr(),
LD->getSrcValue(), LD->getSrcValueOffset(),
LD->getMemoryVT(), LD->isVolatile(),
MemVT, LD->isVolatile(),
LD->isNonTemporal(), LD->getAlignment());
SDValue Result = DAG.getNode(ISD::TRUNCATE, dl, VT, NewLD);
@ -888,6 +901,7 @@ bool DAGCombiner::PromoteLoad(SDValue Op) {
DAG.ReplaceAllUsesOfValueWith(SDValue(N, 1), NewLD.getValue(1), &DeadNodes);
removeFromWorkList(N);
DAG.DeleteNode(N);
AddToWorkList(Result.getNode());
return true;
}
return false;