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Fix for PR3040: 

The CC was changed, but wasn't checked to see if it was legal if the DAG
combiner was being run after legalization. Threw in a couple of checks just to
make sure that it's okay. As far as the PR is concerned, no back-end target
actually exhibited this problem, so there isn't an associated testcase.

llvm-svn: 59035
This commit is contained in:
Bill Wendling 2008-11-11 08:25:46 +00:00
parent 5b1964b5f9
commit 49a5ce863e
1 changed files with 35 additions and 18 deletions
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53
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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@ -892,16 +892,18 @@ SDValue combineShlAddConstant(SDValue N0, SDValue N1, SelectionDAG &DAG) {
static
SDValue combineSelectAndUse(SDNode *N, SDValue Slct, SDValue OtherOp,
SelectionDAG &DAG) {
SelectionDAG &DAG, const TargetLowering &TLI,
bool AfterLegalize) {
MVT VT = N->getValueType(0);
unsigned Opc = N->getOpcode();
bool isSlctCC = Slct.getOpcode() == ISD::SELECT_CC;
SDValue LHS = isSlctCC ? Slct.getOperand(2) : Slct.getOperand(1);
SDValue RHS = isSlctCC ? Slct.getOperand(3) : Slct.getOperand(2);
ISD::CondCode CC = ISD::SETCC_INVALID;
if (isSlctCC)
if (isSlctCC) {
CC = cast<CondCodeSDNode>(Slct.getOperand(4))->get();
else {
} else {
SDValue CCOp = Slct.getOperand(0);
if (CCOp.getOpcode() == ISD::SETCC)
CC = cast<CondCodeSDNode>(CCOp.getOperand(2))->get();
@ -911,17 +913,23 @@ SDValue combineSelectAndUse(SDNode *N, SDValue Slct, SDValue OtherOp,
bool InvCC = false;
assert ((Opc == ISD::ADD || (Opc == ISD::SUB && Slct == N->getOperand(1))) &&
"Bad input!");
if (LHS.getOpcode() == ISD::Constant &&
cast<ConstantSDNode>(LHS)->isNullValue())
cast<ConstantSDNode>(LHS)->isNullValue()) {
DoXform = true;
else if (CC != ISD::SETCC_INVALID &&
RHS.getOpcode() == ISD::Constant &&
cast<ConstantSDNode>(RHS)->isNullValue()) {
} else if (CC != ISD::SETCC_INVALID &&
RHS.getOpcode() == ISD::Constant &&
cast<ConstantSDNode>(RHS)->isNullValue()) {
std::swap(LHS, RHS);
SDValue Op0 = Slct.getOperand(0);
bool isInt = (isSlctCC ? Op0.getValueType() :
Op0.getOperand(0).getValueType()).isInteger();
MVT OpVT = isSlctCC ? Op0.getValueType() :
Op0.getOperand(0).getValueType();
bool isInt = OpVT.isInteger();
CC = ISD::getSetCCInverse(CC, isInt);
if (AfterLegalize && !TLI.isCondCodeLegal(CC, OpVT))
return SDValue(); // Inverse operator isn't legal.
DoXform = true;
InvCC = true;
}
@ -1029,11 +1037,11 @@ SDValue DAGCombiner::visitADD(SDNode *N) {
// fold (add (select cc, 0, c), x) -> (select cc, x, (add, x, c))
if (N0.getOpcode() == ISD::SELECT && N0.getNode()->hasOneUse()) {
SDValue Result = combineSelectAndUse(N, N0, N1, DAG);
SDValue Result = combineSelectAndUse(N, N0, N1, DAG, TLI, AfterLegalize);
if (Result.getNode()) return Result;
}
if (N1.getOpcode() == ISD::SELECT && N1.getNode()->hasOneUse()) {
SDValue Result = combineSelectAndUse(N, N1, N0, DAG);
SDValue Result = combineSelectAndUse(N, N1, N0, DAG, TLI, AfterLegalize);
if (Result.getNode()) return Result;
}
@ -1131,7 +1139,7 @@ SDValue DAGCombiner::visitSUB(SDNode *N) {
return N0.getOperand(0);
// fold (sub x, (select cc, 0, c)) -> (select cc, x, (sub, x, c))
if (N1.getOpcode() == ISD::SELECT && N1.getNode()->hasOneUse()) {
SDValue Result = combineSelectAndUse(N, N1, N0, DAG);
SDValue Result = combineSelectAndUse(N, N1, N0, DAG, TLI, AfterLegalize);
if (Result.getNode()) return Result;
}
// If either operand of a sub is undef, the result is undef
@ -2156,18 +2164,27 @@ SDValue DAGCombiner::visitXOR(SDNode *N) {
SDValue RXOR = ReassociateOps(ISD::XOR, N0, N1);
if (RXOR.getNode() != 0)
return RXOR;
// fold !(x cc y) -> (x !cc y)
if (N1C && N1C->getAPIntValue() == 1 && isSetCCEquivalent(N0, LHS, RHS, CC)) {
bool isInt = LHS.getValueType().isInteger();
ISD::CondCode NotCC = ISD::getSetCCInverse(cast<CondCodeSDNode>(CC)->get(),
isInt);
if (N0.getOpcode() == ISD::SETCC)
return DAG.getSetCC(VT, LHS, RHS, NotCC);
if (N0.getOpcode() == ISD::SELECT_CC)
return DAG.getSelectCC(LHS, RHS, N0.getOperand(2),N0.getOperand(3),NotCC);
assert(0 && "Unhandled SetCC Equivalent!");
abort();
if (!AfterLegalize || TLI.isCondCodeLegal(NotCC, LHS.getValueType())) {
switch (N0.getOpcode()) {
default:
assert(0 && "Unhandled SetCC Equivalent!");
abort();
case ISD::SETCC:
return DAG.getSetCC(VT, LHS, RHS, NotCC);
case ISD::SELECT_CC:
return DAG.getSelectCC(LHS, RHS, N0.getOperand(2),
N0.getOperand(3), NotCC);
}
}
}
// fold (not (zext (setcc x, y))) -> (zext (not (setcc x, y)))
if (N1C && N1C->getAPIntValue() == 1 && N0.getOpcode() == ISD::ZERO_EXTEND &&
N0.getNode()->hasOneUse() &&