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Implement some feedback from sabre 

llvm-svn: 25946
This commit is contained in:
Nate Begeman 2006-02-03 22:38:07 +00:00
parent dc7bba9ffe
commit 20a894282d
1 changed files with 5 additions and 5 deletions
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10
llvm/lib/Target/TargetLowering.cpp
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@ -135,14 +135,14 @@ const char *TargetLowering::getTargetNodeName(unsigned Opcode) const {
/// set operation such as a sign extend or or/xor with constant whose only
/// use is Op. If it returns true, the old node that sets bits which are
/// not demanded is returned in Old, and its replacement node is returned in
/// New, such that callers of SetBitsAreZero may call CombineTo on them if
/// New, such that callers of DemandedBitsAreZero may call CombineTo on them if
/// desired.
bool TargetLowering::DemandedBitsAreZero(const SDOperand &Op, uint64_t Mask,
SDOperand &Old, SDOperand &New,
SelectionDAG &DAG) {
// If the operation has more than one use, we're not interested in it.
// Tracking down and checking all uses would be problematic and slow.
if (!Op.hasOneUse())
if (!Op.Val->hasOneUse())
return false;
switch (Op.getOpcode()) {
@ -164,11 +164,11 @@ bool TargetLowering::DemandedBitsAreZero(const SDOperand &Op, uint64_t Mask,
MVT::ValueType EVT = cast<VTSDNode>(Op.getOperand(1))->getVT();
unsigned ExtendBits = MVT::getSizeInBits(EVT);
// If we're extending from something smaller than MVT::i64 and all of the
// sign extension bits are masked, return true and set New to be a zero
// extend inreg from the same type.
// sign extension bits are masked, return true and set New to be the
// first operand, since we no longer care what the high bits are.
if (ExtendBits < 64 && ((Mask & (~0ULL << ExtendBits)) == 0)) {
Old = Op;
New = DAG.getZeroExtendInReg(Op.getOperand(0), EVT);
New = Op.getOperand(0);
return true;
}
break;