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Disbale the broken fold of shift + sz[ext] for now

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Move the transform for select (a < 0) ? b : 0 into the dag from ppc isel
Enable the dag to fold and (setcc, 1) -> setcc for targets where setcc
  always produces zero or one.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21291 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Nate Begeman
2005-04-13 21:23:31 +00:00
parent 97e001dec7
commit eea805e74c
2 changed files with 30 additions and 26 deletions
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37
lib/CodeGen/SelectionDAG/SelectionDAG.cpp
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@@ -773,7 +773,7 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
case ISD::AND:
if (!C2) return N2; // X and 0 -> 0
if (N2C->isAllOnesValue())
return N1; // X and -1 -> X
return N1; // X and -1 -> X
// FIXME: Should add a corresponding version of this for
// ZERO_EXTEND/SIGN_EXTEND by converting them to an ANY_EXTEND node which
@@ -795,13 +795,13 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
// If we are anding the result of a setcc, and we know setcc always
// returns 0 or 1, simplify the RHS to either be 0 or 1
if (N1.getOpcode() == ISD::SETCC && C2 != 1 &&
if (N1.getOpcode() == ISD::SETCC &&
TLI.getSetCCResultContents() == TargetLowering::ZeroOrOneSetCCResult)
if (C2 & 1)
return getNode(ISD::AND, VT, N1, getConstant(1, VT));
return N1;
else
return getConstant(0, VT);
if (N1.getOpcode() == ISD::ZEXTLOAD) {
// If we are anding the result of a zext load, realize that the top bits
// of the loaded value are already zero to simplify C2.
@@ -941,6 +941,10 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
if (N2.getOpcode() == ISD::FNEG) // (A- (-B) -> A+B
return getNode(ISD::ADD, VT, N1, N2.getOperand(0));
break;
// FIXME: figure out how to safely handle things like
// int foo(int x) { return 1 << (x & 255); }
// int bar() { return foo(256); }
#if 0
case ISD::SHL:
case ISD::SRL:
case ISD::SRA:
@@ -955,8 +959,8 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
if ((AndRHS->getValue() & (NumBits-1)) == NumBits-1)
return getNode(Opcode, VT, N1, N2.getOperand(0));
}
break;
#endif
}
SDNode *&N = BinaryOps[std::make_pair(Opcode, std::make_pair(N1, N2))];
@@ -1039,6 +1043,22 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
N2.getOperand(0) == N3)
return getNode(ISD::FABS, VT, N3);
}
// select (setlt X, 0), A, 0 -> and (sra X, size(X)-1, A)
if (ConstantSDNode *CN =
dyn_cast<ConstantSDNode>(SetCC->getOperand(1)))
if (CN->getValue() == 0 && N3C && N3C->getValue() == 0)
if (SetCC->getCondition() == ISD::SETLT) {
MVT::ValueType XType = SetCC->getOperand(0).getValueType();
MVT::ValueType AType = N2.getValueType();
if (XType >= AType) {
SDOperand Shift = getNode(ISD::SRA, XType, SetCC->getOperand(0),
getConstant(MVT::getSizeInBits(XType)-1,
TLI.getShiftAmountTy()));
if (XType > AType)
Shift = getNode(ISD::TRUNCATE, AType, Shift);
return getNode(ISD::AND, AType, Shift, N2);
}
}
}
break;
case ISD::BRCOND:
@@ -1048,6 +1068,10 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
else
return N1; // Never-taken branch
break;
// FIXME: figure out how to safely handle things like
// int foo(int x) { return 1 << (x & 255); }
// int bar() { return foo(256); }
#if 0
case ISD::SRA_PARTS:
case ISD::SRL_PARTS:
case ISD::SHL_PARTS:
@@ -1062,9 +1086,8 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
if ((AndRHS->getValue() & (NumBits-1)) == NumBits-1)
return getNode(Opcode, VT, N1, N2, N3.getOperand(0));
}
break;
#endif
}
SDNode *N = new SDNode(Opcode, N1, N2, N3);