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When trying to fold X86::SETCC into a Select, make a copy if it has more than 

one use. This allows more CMOV instructions.

llvm-svn: 25634
This commit is contained in:
Evan Cheng 2006-01-26 02:13:10 +00:00
parent 120f31b1fd
commit 944d1e91ea
1 changed files with 22 additions and 6 deletions
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28
llvm/lib/Target/X86/X86ISelLowering.cpp
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@ -1669,9 +1669,17 @@ SDOperand X86TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
// If the X86ISD::SETCC has more than one use, then it's probably better // If the X86ISD::SETCC has more than one use, then it's probably better
// to use a test instead of duplicating the X86ISD::CMP (for register // to use a test instead of duplicating the X86ISD::CMP (for register
// pressure reason). // pressure reason).
// FIXME: Check number of live Op0 uses since we are in the middle of if (Op0.getOperand(1).getOpcode() == X86ISD::CMP) {
// legalization process. if (!Op0.hasOneUse()) {
if (Op0.hasOneUse() && Op0.getOperand(1).getOpcode() == X86ISD::CMP) { std::vector<MVT::ValueType> Tys;
for (unsigned i = 0; i < Op0.Val->getNumValues(); ++i)
Tys.push_back(Op0.Val->getValueType(i));
std::vector<SDOperand> Ops;
for (unsigned i = 0; i < Op0.getNumOperands(); ++i)
Ops.push_back(Op0.getOperand(i));
Op0 = DAG.getNode(X86ISD::SETCC, Tys, Ops);
}
CC = Op0.getOperand(0); CC = Op0.getOperand(0);
Cond = Op0.getOperand(1); Cond = Op0.getOperand(1);
// Make a copy as flag result cannot be used by more than one. // Make a copy as flag result cannot be used by more than one.
@ -1720,9 +1728,17 @@ SDOperand X86TargetLowering::LowerOperation(SDOperand Op, SelectionDAG &DAG) {
// If the X86ISD::SETCC has more than one use, then it's probably better // If the X86ISD::SETCC has more than one use, then it's probably better
// to use a test instead of duplicating the X86ISD::CMP (for register // to use a test instead of duplicating the X86ISD::CMP (for register
// pressure reason). // pressure reason).
// FIXME: Check number of live Cond uses since we are in the middle of if (Cond.getOperand(1).getOpcode() == X86ISD::CMP) {
// legalization process. if (!Cond.hasOneUse()) {
if (Cond.hasOneUse() && Cond.getOperand(1).getOpcode() == X86ISD::CMP) { std::vector<MVT::ValueType> Tys;
for (unsigned i = 0; i < Cond.Val->getNumValues(); ++i)
Tys.push_back(Cond.Val->getValueType(i));
std::vector<SDOperand> Ops;
for (unsigned i = 0; i < Cond.getNumOperands(); ++i)
Ops.push_back(Cond.getOperand(i));
Cond = DAG.getNode(X86ISD::SETCC, Tys, Ops);
}
CC = Cond.getOperand(0); CC = Cond.getOperand(0);
Cond = Cond.getOperand(1); Cond = Cond.getOperand(1);
// Make a copy as flag result cannot be used by more than one. // Make a copy as flag result cannot be used by more than one.