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implement some more logical compares with constants, so that:

Browse Source 
int foo1(int x, int y) {
  int t1 = x >= 0;
  int t2 = y >= 0;
  return t1 & t2;
}
int foo2(int x, int y) {
  int t1 = x == -1;
  int t2 = y == -1;
  return t1 & t2;
}

produces:

_foo1:
        or r2, r4, r3
        srwi r2, r2, 31
        xori r3, r2, 1
        blr
_foo2:
        and r2, r4, r3
        addic r2, r2, 1
        li r2, 0
        addze r3, r2
        blr

instead of:

_foo1:
        srwi r2, r4, 31
        xori r2, r2, 1
        srwi r3, r3, 31
        xori r3, r3, 1
        and r3, r2, r3
        blr
_foo2:
        addic r2, r4, 1
        li r2, 0
        addze r2, r2
        addic r3, r3, 1
        li r3, 0
        addze r3, r3
        and r3, r2, r3
        blr

llvm-svn: 21547
This commit is contained in:
Chris Lattner 2005-04-25 21:20:28 +00:00
parent 9b66533e40
commit d8ac4da793
1 changed files with 20 additions and 7 deletions
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27
lib/CodeGen/SelectionDAG/SelectionDAG.cpp
View File

@ -1060,17 +1060,30 @@ SDOperand SelectionDAG::getNode(unsigned Opcode, MVT::ValueType VT,
SDOperand LR = LHS->getOperand(1), RR = RHS->getOperand(1);
ISD::CondCode Op2 = RHS->getCondition();
// (X != 0) | (Y != 0) -> (X|Y != 0)
// (X == 0) & (Y == 0) -> (X|Y == 0)
// (X < 0) | (Y < 0) -> (X|Y < 0)
if (LR == RR && isa<ConstantSDNode>(LR) &&
cast<ConstantSDNode>(LR)->getValue() == 0 &&
Op2 == LHS->getCondition() && MVT::isInteger(LL.getValueType())) {
if ((Op2 == ISD::SETEQ && Opcode == ISD::AND) ||
(Op2 == ISD::SETNE && Opcode == ISD::OR) ||
(Op2 == ISD::SETLT && Opcode == ISD::OR))
// (X != 0) | (Y != 0) -> (X|Y != 0)
// (X == 0) & (Y == 0) -> (X|Y == 0)
// (X < 0) | (Y < 0) -> (X|Y < 0)
if (cast<ConstantSDNode>(LR)->getValue() == 0 &&
((Op2 == ISD::SETEQ && Opcode == ISD::AND) ||
(Op2 == ISD::SETNE && Opcode == ISD::OR) ||
(Op2 == ISD::SETLT && Opcode == ISD::OR)))
return getSetCC(Op2, VT,
getNode(ISD::OR, LR.getValueType(), LL, RL), LR);
if (cast<ConstantSDNode>(LR)->isAllOnesValue()) {
// (X == -1) & (Y == -1) -> (X&Y == -1)
// (X != -1) | (Y != -1) -> (X&Y != -1)
if ((Opcode == ISD::AND && Op2 == ISD::SETEQ) ||
(Opcode == ISD::OR && Op2 == ISD::SETNE))
return getSetCC(Op2, VT,
getNode(ISD::AND, LR.getValueType(), LL, RL), LR);
// (X > -1) & (Y > -1) -> (X|Y > -1)
if (Opcode == ISD::AND && Op2 == ISD::SETGT)
return getSetCC(Op2, VT,
getNode(ISD::OR, LR.getValueType(), LL, RL), LR);
}
}
// (X op1 Y) | (Y op2 X) -> (X op1 Y) | (X swapop2 Y)