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improved zap discovery

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@26148 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Andrew Lenharth 2006-02-13 18:52:29 +00:00
parent bd7c22cdcc
commit 40ec5037fa
1 changed files with 33 additions and 0 deletions
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33
lib/Target/Alpha/AlphaISelDAGToDAG.cpp
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@ -363,6 +363,39 @@ void AlphaDAGToDAGISel::Select(SDOperand &Result, SDOperand Op) {
}
break;
case ISD::AND: {
ConstantSDNode* SC;
ConstantSDNode* MC;
if (N->getOperand(0).getOpcode() == ISD::SRL &&
(MC = dyn_cast<ConstantSDNode>(N->getOperand(1))) &&
(SC = dyn_cast<ConstantSDNode>(N->getOperand(0).getOperand(1))))
{
uint64_t sval = SC->getValue();
uint64_t mval = MC->getValue();
if (get_zapImm(mval)) //the result is a zap, let the autogened stuff deal
break;
// given mask X, and shift S, we want to see if there is any zap in the mask
// if we play around with the botton S bits
uint64_t dontcare = (~0ULL) >> (64 - sval);
uint64_t mask = mval << sval;
if (get_zapImm(mask | dontcare))
mask = mask | dontcare;
if (get_zapImm(mask)) {
SDOperand Src;
Select(Src, N->getOperand(0).getOperand(0));
SDOperand Z =
SDOperand(CurDAG->getTargetNode(Alpha::ZAPNOTi, MVT::i64, Src,
getI64Imm(get_zapImm(mask))), 0);
Result = SDOperand(CurDAG->getTargetNode(Alpha::SRL, MVT::i64, Z,
getI64Imm(sval)), 0);
return;
}
}
break;
}
}
SelectCode(Result, Op);