don't create shifts by zero, fix some problems with my previous patch

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35887 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2007-04-11 06:43:25 +00:00
parent ba41783dbb
commit c56a81dff1

View File

@ -2136,7 +2136,7 @@ SDOperand DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
SimplifySelectCC(N0.getOperand(0), N0.getOperand(1),
DAG.getConstant(~0ULL, VT), DAG.getConstant(0, VT),
cast<CondCodeSDNode>(N0.getOperand(2))->get());
if (SCC.Val) return SCC;
if (SCC.Val && SCC.Val != N) return SCC;
}
return SDOperand();
@ -2226,7 +2226,7 @@ SDOperand DAGCombiner::visitZERO_EXTEND(SDNode *N) {
SimplifySelectCC(N0.getOperand(0), N0.getOperand(1),
DAG.getConstant(1, VT), DAG.getConstant(0, VT),
cast<CondCodeSDNode>(N0.getOperand(2))->get());
if (SCC.Val) return SCC;
if (SCC.Val && SCC.Val != N) return SCC;
}
return SDOperand();
@ -2320,7 +2320,8 @@ SDOperand DAGCombiner::visitANY_EXTEND(SDNode *N) {
SimplifySelectCC(N0.getOperand(0), N0.getOperand(1),
DAG.getConstant(1, VT), DAG.getConstant(0, VT),
cast<CondCodeSDNode>(N0.getOperand(2))->get());
if (SCC.Val) return SCC;
if (SCC.Val && SCC.Val != N && SCC.getOpcode() != ISD::ZERO_EXTEND)
return SCC;
}
return SDOperand();
@ -4139,6 +4140,9 @@ SDOperand DAGCombiner::SimplifySelectCC(SDOperand N0, SDOperand N1,
}
AddToWorkList(SCC.Val);
AddToWorkList(Temp.Val);
if (N2C->getValue() == 1)
return Temp;
// shl setcc result by log2 n2c
return DAG.getNode(ISD::SHL, N2.getValueType(), Temp,
DAG.getConstant(Log2_64(N2C->getValue()),