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If both parts of smul_lohi, etc. are used, don't simplify. If only one part is used, try simplify it.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43888 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng
2007-11-08 09:25:29 +00:00
parent 01f43a4d55
commit 4471194d69
2 changed files with 160 additions and 30 deletions
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61
lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@@ -1420,7 +1420,8 @@ SDOperand DAGCombiner::visitMULHU(SDNode *N) {
bool DAGCombiner::SimplifyNodeWithTwoResults(SDNode *N,
unsigned LoOp, unsigned HiOp) {
// If the high half is not needed, just compute the low half.
if (!N->hasAnyUseOfValue(1) &&
bool HiExists = N->hasAnyUseOfValue(1);
if (!HiExists &&
(!AfterLegalize ||
TLI.isOperationLegal(LoOp, N->getValueType(0)))) {
DAG.ReplaceAllUsesOfValueWith(SDOperand(N, 0),
@@ -1431,7 +1432,8 @@ bool DAGCombiner::SimplifyNodeWithTwoResults(SDNode *N,
}
// If the low half is not needed, just compute the high half.
if (!N->hasAnyUseOfValue(0) &&
bool LoExists = N->hasAnyUseOfValue(0);
if (!LoExists &&
(!AfterLegalize ||
TLI.isOperationLegal(HiOp, N->getValueType(1)))) {
DAG.ReplaceAllUsesOfValueWith(SDOperand(N, 1),
@@ -1441,36 +1443,35 @@ bool DAGCombiner::SimplifyNodeWithTwoResults(SDNode *N,
return true;
}
// If the two computed results can be siplified separately, separate them.
SDOperand Lo = DAG.getNode(LoOp, N->getValueType(0),
N->op_begin(), N->getNumOperands());
SDOperand Hi = DAG.getNode(HiOp, N->getValueType(1),
N->op_begin(), N->getNumOperands());
unsigned LoExists = !Lo.use_empty();
unsigned HiExists = !Hi.use_empty();
SDOperand LoOpt = Lo;
SDOperand HiOpt = Hi;
if (!LoExists || !HiExists) {
SDOperand Pair = DAG.getNode(ISD::BUILD_PAIR, MVT::Other, Lo, Hi);
assert(Pair.use_empty() && "Pair with type MVT::Other already exists!");
LoOpt = combine(Lo.Val);
HiOpt = combine(Hi.Val);
if (!LoOpt.Val)
LoOpt = Pair.getOperand(0);
if (!HiOpt.Val)
HiOpt = Pair.getOperand(1);
DAG.DeleteNode(Pair.Val);
}
if ((LoExists || LoOpt != Lo) &&
(HiExists || HiOpt != Hi) &&
TLI.isOperationLegal(LoOpt.getOpcode(), LoOpt.getValueType()) &&
TLI.isOperationLegal(HiOpt.getOpcode(), HiOpt.getValueType())) {
DAG.ReplaceAllUsesOfValueWith(SDOperand(N, 0), LoOpt);
DAG.ReplaceAllUsesOfValueWith(SDOperand(N, 1), HiOpt);
return true;
// If both halves are used, return as it is.
if (LoExists && HiExists)
return false;
// If the two computed results can be simplified separately, separate them.
bool RetVal = false;
if (LoExists) {
SDOperand Lo = DAG.getNode(LoOp, N->getValueType(0),
N->op_begin(), N->getNumOperands());
SDOperand LoOpt = combine(Lo.Val);
if (LoOpt.Val && LoOpt != Lo &&
TLI.isOperationLegal(LoOpt.getOpcode(), LoOpt.getValueType())) {
RetVal = true;
DAG.ReplaceAllUsesOfValueWith(SDOperand(N, 0), LoOpt);
}
}
return false;
if (HiExists) {
SDOperand Hi = DAG.getNode(HiOp, N->getValueType(1),
N->op_begin(), N->getNumOperands());
SDOperand HiOpt = combine(Hi.Val);
if (HiOpt.Val && HiOpt != Hi &&
TLI.isOperationLegal(HiOpt.getOpcode(), HiOpt.getValueType())) {
RetVal = true;
DAG.ReplaceAllUsesOfValueWith(SDOperand(N, 1), HiOpt);
}
}
return RetVal;
}
SDOperand DAGCombiner::visitSMUL_LOHI(SDNode *N) {