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Fix a bug emitting branches that broke a lot of programs.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19452 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2005-01-11 04:06:27 +00:00
parent ef7ba0756b
commit 6c07aee7c9
1 changed files with 22 additions and 12 deletions
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32
lib/Target/X86/X86ISelPattern.cpp
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@ -362,7 +362,7 @@ namespace {
} }
void EmitCMP(SDOperand LHS, SDOperand RHS); void EmitCMP(SDOperand LHS, SDOperand RHS);
bool EmitBranchCC(MachineBasicBlock *Dest, SDOperand Cond); bool EmitBranchCC(MachineBasicBlock *Dest, SDOperand Chain, SDOperand Cond);
void EmitSelectCC(SDOperand Cond, MVT::ValueType SVT, void EmitSelectCC(SDOperand Cond, MVT::ValueType SVT,
unsigned RTrue, unsigned RFalse, unsigned RDest); unsigned RTrue, unsigned RFalse, unsigned RDest);
unsigned SelectExpr(SDOperand N); unsigned SelectExpr(SDOperand N);
@ -559,7 +559,8 @@ static void EmitSetCC(MachineBasicBlock *BB, unsigned DestReg,
/// the Dest block if the Cond condition is true. If we cannot fold this /// the Dest block if the Cond condition is true. If we cannot fold this
/// condition into the branch, return true. /// condition into the branch, return true.
/// ///
bool ISel::EmitBranchCC(MachineBasicBlock *Dest, SDOperand Cond) { bool ISel::EmitBranchCC(MachineBasicBlock *Dest, SDOperand Chain,
SDOperand Cond) {
// FIXME: Evaluate whether it would be good to emit code like (X < Y) | (A > // FIXME: Evaluate whether it would be good to emit code like (X < Y) | (A >
// B) using two conditional branches instead of one condbr, two setcc's, and // B) using two conditional branches instead of one condbr, two setcc's, and
// an or. // an or.
@ -568,6 +569,7 @@ bool ISel::EmitBranchCC(MachineBasicBlock *Dest, SDOperand Cond) {
// And and or set the flags for us, so there is no need to emit a TST of the // And and or set the flags for us, so there is no need to emit a TST of the
// result. It is only safe to do this if there is only a single use of the // result. It is only safe to do this if there is only a single use of the
// AND/OR though, otherwise we don't know it will be emitted here. // AND/OR though, otherwise we don't know it will be emitted here.
Select(Chain);
SelectExpr(Cond); SelectExpr(Cond);
BuildMI(BB, X86::JNE, 1).addMBB(Dest); BuildMI(BB, X86::JNE, 1).addMBB(Dest);
return false; return false;
@ -577,7 +579,14 @@ bool ISel::EmitBranchCC(MachineBasicBlock *Dest, SDOperand Cond) {
if (Cond.getOpcode() == ISD::XOR) if (Cond.getOpcode() == ISD::XOR)
if (ConstantSDNode *NC = dyn_cast<ConstantSDNode>(Cond.Val->getOperand(1))) if (ConstantSDNode *NC = dyn_cast<ConstantSDNode>(Cond.Val->getOperand(1)))
if (NC->isAllOnesValue()) { if (NC->isAllOnesValue()) {
unsigned CondR = SelectExpr(Cond.Val->getOperand(0)); unsigned CondR;
if (getRegPressure(Chain) > getRegPressure(Cond)) {
Select(Chain);
CondR = SelectExpr(Cond.Val->getOperand(0));
} else {
CondR = SelectExpr(Cond.Val->getOperand(0));
Select(Chain);
}
BuildMI(BB, X86::TEST8rr, 2).addReg(CondR).addReg(CondR); BuildMI(BB, X86::TEST8rr, 2).addReg(CondR).addReg(CondR);
BuildMI(BB, X86::JE, 1).addMBB(Dest); BuildMI(BB, X86::JE, 1).addMBB(Dest);
return false; return false;
@ -604,6 +613,7 @@ bool ISel::EmitBranchCC(MachineBasicBlock *Dest, SDOperand Cond) {
case ISD::SETULE: Opc = X86::JBE; break; case ISD::SETULE: Opc = X86::JBE; break;
case ISD::SETUGE: Opc = X86::JAE; break; case ISD::SETUGE: Opc = X86::JAE; break;
} }
Select(Chain);
EmitCMP(SetCC->getOperand(0), SetCC->getOperand(1)); EmitCMP(SetCC->getOperand(0), SetCC->getOperand(1));
BuildMI(BB, Opc, 1).addMBB(Dest); BuildMI(BB, Opc, 1).addMBB(Dest);
return false; return false;
@ -660,6 +670,7 @@ bool ISel::EmitBranchCC(MachineBasicBlock *Dest, SDOperand Cond) {
return true; // FIXME: Emit more efficient code for this branch. return true; // FIXME: Emit more efficient code for this branch.
} }
Select(Chain);
EmitCMP(SetCC->getOperand(0), SetCC->getOperand(1)); EmitCMP(SetCC->getOperand(0), SetCC->getOperand(1));
BuildMI(BB, Opc, 1).addMBB(Dest); BuildMI(BB, Opc, 1).addMBB(Dest);
if (Opc2) if (Opc2)
@ -1906,21 +1917,20 @@ void ISel::Select(SDOperand N) {
MachineBasicBlock *Dest = MachineBasicBlock *Dest =
cast<BasicBlockSDNode>(N.getOperand(2))->getBasicBlock(); cast<BasicBlockSDNode>(N.getOperand(2))->getBasicBlock();
bool ChainFirst =
getRegPressure(N.getOperand(0)) > getRegPressure(N.getOperand(1));
if (ChainFirst) Select(N.getOperand(0));
// Try to fold a setcc into the branch. If this fails, emit a test/jne // Try to fold a setcc into the branch. If this fails, emit a test/jne
// pair. // pair.
if (EmitBranchCC(Dest, N.getOperand(1))) { if (EmitBranchCC(Dest, N.getOperand(0), N.getOperand(1))) {
if (getRegPressure(N.getOperand(0)) > getRegPressure(N.getOperand(1))) {
Select(N.getOperand(0));
Tmp1 = SelectExpr(N.getOperand(1)); Tmp1 = SelectExpr(N.getOperand(1));
} else {
Tmp1 = SelectExpr(N.getOperand(1));
Select(N.getOperand(0));
}
BuildMI(BB, X86::TEST8rr, 2).addReg(Tmp1).addReg(Tmp1); BuildMI(BB, X86::TEST8rr, 2).addReg(Tmp1).addReg(Tmp1);
BuildMI(BB, X86::JNE, 1).addMBB(Dest); BuildMI(BB, X86::JNE, 1).addMBB(Dest);
} }
if (!ChainFirst) Select(N.getOperand(0));
return; return;
} }
case ISD::LOAD: case ISD::LOAD: