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Codegen cond&cond with two branches. This compiles (f.e.) PowerPC/and-branch.ll to:

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cmpwi cr0, r4, 4
        bgt cr0, LBB1_2 ;UnifiedReturnBlock
LBB1_3: ;entry
        cmplwi cr0, r3, 0
        bne cr0, LBB1_2 ;UnifiedReturnBlock

instead of:

        cmpwi cr7, r4, 4
        mfcr r2
        addic r4, r3, -1
        subfe r3, r4, r3
        rlwinm r2, r2, 30, 31, 31
        or r2, r2, r3
        cmplwi cr0, r2, 0
        bne cr0, LBB1_2 ;UnifiedReturnBlock
LBB1_1: ;cond_true


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@31232 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2006-10-27 21:54:23 +00:00
parent 00ef504797
commit d2f9ee9ea7
1 changed files with 35 additions and 15 deletions
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50
lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
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@ -888,22 +888,43 @@ void SelectionDAGLowering::FindMergedConditions(Value *Cond,
return;
}
// Codegen X | Y as:
// jmp_if_X TBB
// TmpBB:
// jmp_if_Y TBB
// jmp FBB
//
// This requires creation of TmpBB after CurBB.
// Create TmpBB after CurBB.
MachineFunction::iterator BBI = CurBB;
MachineBasicBlock *TmpBB = new MachineBasicBlock(CurBB->getBasicBlock());
CurBB->getParent()->getBasicBlockList().insert(++BBI, TmpBB);
// Emit the LHS condition.
FindMergedConditions(BOp->getOperand(0), TBB, TmpBB, CurBB, Opc);
if (Opc == Instruction::Or) {
// Codegen X | Y as:
// jmp_if_X TBB
// jmp TmpBB
// TmpBB:
// jmp_if_Y TBB
// jmp FBB
//
// Emit the RHS condition into TmpBB.
FindMergedConditions(BOp->getOperand(1), TBB, FBB, TmpBB, Opc);
// Emit the LHS condition.
FindMergedConditions(BOp->getOperand(0), TBB, TmpBB, CurBB, Opc);
// Emit the RHS condition into TmpBB.
FindMergedConditions(BOp->getOperand(1), TBB, FBB, TmpBB, Opc);
} else {
assert(Opc == Instruction::And && "Unknown merge op!");
// Codegen X & Y as:
// jmp_if_X TmpBB
// jmp FBB
// TmpBB:
// jmp_if_Y TBB
// jmp FBB
//
// This requires creation of TmpBB after CurBB.
// Emit the LHS condition.
FindMergedConditions(BOp->getOperand(0), TmpBB, FBB, CurBB, Opc);
// Emit the RHS condition into TmpBB.
FindMergedConditions(BOp->getOperand(1), TBB, FBB, TmpBB, Opc);
}
}
void SelectionDAGLowering::visitBr(BranchInst &I) {
@ -950,12 +971,11 @@ void SelectionDAGLowering::visitBr(BranchInst &I) {
//
if (BinaryOperator *BOp = dyn_cast<BinaryOperator>(CondVal)) {
if (BOp->hasOneUse() &&
(/*BOp->getOpcode() == Instruction::And ||*/
(BOp->getOpcode() == Instruction::And ||
BOp->getOpcode() == Instruction::Or)) {
if (BOp->getOpcode() == Instruction::And)
I.getParent()->dump();
FindMergedConditions(BOp, Succ0MBB, Succ1MBB, CurMBB, BOp->getOpcode());
//std::cerr << "FOUND: " << SwitchCases.size() << " merged conditions:\n";
//I.getParent()->dump();
visitSwitchCase(SwitchCases[0]);
SwitchCases.erase(SwitchCases.begin());
return;