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fold (aext (and (trunc x), cst)) -> (and x, cst). 

llvm-svn: 30561
This commit is contained in:
Chris Lattner 2006-09-21 06:40:43 +00:00
parent fa9f92cf65
commit 082db3f9aa
1 changed files with 15 additions and 0 deletions
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15
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -1897,6 +1897,21 @@ SDOperand DAGCombiner::visitANY_EXTEND(SDNode *N) {
return DAG.getNode(ISD::TRUNCATE, VT, TruncOp);
return DAG.getNode(ISD::ANY_EXTEND, VT, TruncOp);
}
// fold (aext (and (trunc x), cst)) -> (and x, cst).
if (N0.getOpcode() == ISD::AND &&
N0.getOperand(0).getOpcode() == ISD::TRUNCATE &&
N0.getOperand(1).getOpcode() == ISD::Constant) {
SDOperand X = N0.getOperand(0).getOperand(0);
if (X.getValueType() < VT) {
X = DAG.getNode(ISD::ANY_EXTEND, VT, X);
} else if (X.getValueType() > VT) {
X = DAG.getNode(ISD::TRUNCATE, VT, X);
}
uint64_t Mask = cast<ConstantSDNode>(N0.getOperand(1))->getValue();
return DAG.getNode(ISD::AND, VT, X, DAG.getConstant(Mask, VT));
}
// fold (aext (load x)) -> (aext (truncate (extload x)))
if (N0.getOpcode() == ISD::LOAD && N0.hasOneUse() &&
(!AfterLegalize||TLI.isOperationLegal(ISD::EXTLOAD, N0.getValueType()))) {