Teach SelectionDAG how to simplify a few more setcc-equivalent select_cc
nodes so that backends don't have to.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22999 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index c7687e3..21f763a 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -853,21 +853,36 @@
}
}
- // Check to see if this is the equivalent of seteq X, 0.
- // select_cc eq X, 0, 1, 0 -> setcc X, 0, eq -> srl (ctlz X), log2(size(X))
- if (N2C && N2C->isNullValue() && N4C && N4C->isNullValue() &&
- N3C && (N3C->getValue() == 1ULL) && CC == ISD::SETEQ) {
+ // Check to see if this is the equivalent of setcc X, 0
+ if (N4C && N4C->isNullValue() && N3C && (N3C->getValue() == 1ULL)) {
MVT::ValueType XType = N1.getValueType();
if (TLI.getOperationAction(ISD::SETCC, TLI.getSetCCResultTy()) ==
TargetLowering::Legal) {
- return getSetCC(TLI.getSetCCResultTy(), N1, N2, ISD::SETEQ);
+ return getSetCC(TLI.getSetCCResultTy(), N1, N2, CC);
}
- if (TLI.getOperationAction(ISD::CTLZ, XType) == TargetLowering::Legal) {
+ // seteq X, 0 -> srl (ctlz X, log2(size(X)))
+ if (N2C && N2C->isNullValue() && CC == ISD::SETEQ &&
+ TLI.getOperationAction(ISD::CTLZ, XType) == TargetLowering::Legal) {
SDOperand Ctlz = getNode(ISD::CTLZ, XType, N1);
return getNode(ISD::SRL, XType, Ctlz,
getConstant(Log2_32(MVT::getSizeInBits(XType)),
TLI.getShiftAmountTy()));
}
+ // setgt X, 0 -> srl (and (-X, ~X), size(X)-1)
+ if (N2C && N2C->isNullValue() && CC == ISD::SETGT) {
+ SDOperand NegN1 = getNode(ISD::SUB, XType, getConstant(0, XType), N1);
+ SDOperand NotN1 = getNode(ISD::XOR, XType, N1, getConstant(~0ULL, XType));
+ return getNode(ISD::SRL, XType, getNode(ISD::AND, XType, NegN1, NotN1),
+ getConstant(MVT::getSizeInBits(XType)-1,
+ TLI.getShiftAmountTy()));
+ }
+ // setgt X, -1 -> xor (srl (X, size(X)-1), 1)
+ if (N2C && N2C->isAllOnesValue() && CC == ISD::SETGT) {
+ SDOperand Sign = getNode(ISD::SRL, XType, N1,
+ getConstant(MVT::getSizeInBits(XType)-1,
+ TLI.getShiftAmountTy()));
+ return getNode(ISD::XOR, XType, Sign, getConstant(1, XType));
+ }
}
// Check to see if this is an integer abs. select_cc setl[te] X, 0, -X, X ->