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Fix bug in -split-phi-edges.

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When splitting an edge after a machine basic block with fall-through, we
forgot to insert a jump instruction. Fix this by calling updateTerminator() on
the fall-through block when relevant.

Also be more precise in PHIElimination::isLiveIn.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88728 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2009-11-14 00:38:13 +00:00
parent 9aebb61daf
commit 3b6ced1510
1 changed files with 14 additions and 3 deletions
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17
lib/CodeGen/PHIElimination.cpp
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@ -64,7 +64,6 @@ bool llvm::PHIElimination::runOnMachineFunction(MachineFunction &Fn) {
PHIDefs.clear();
PHIKills.clear();
bool Changed = false;
// Split critical edges to help the coalescer
@ -419,7 +418,16 @@ bool llvm::PHIElimination::isLiveIn(unsigned Reg, const MachineBasicBlock &MBB,
LiveVariables &LV) {
LiveVariables::VarInfo &VI = LV.getVarInfo(Reg);
return VI.AliveBlocks.test(MBB.getNumber()) || VI.findKill(&MBB);
if (VI.AliveBlocks.test(MBB.getNumber()))
return true;
// defined in MBB?
const MachineInstr *Def = MRI->getVRegDef(Reg);
if (Def && Def->getParent() == &MBB)
return false;
// killed in MBB?
return VI.findKill(&MBB);
}
MachineBasicBlock *PHIElimination::SplitCriticalEdge(MachineBasicBlock *A,
@ -436,9 +444,12 @@ MachineBasicBlock *PHIElimination::SplitCriticalEdge(MachineBasicBlock *A,
<< " -- BB#" << B->getNumber() << '\n');
A->ReplaceUsesOfBlockWith(B, NMBB);
NMBB->addSuccessor(B);
// If A may fall through to B, we may have to insert a branch.
if (A->isLayoutSuccessor(B))
A->updateTerminator();
// Insert unconditional "jump B" instruction in NMBB.
NMBB->addSuccessor(B);
SmallVector<MachineOperand, 4> Cond;
MF->getTarget().getInstrInfo()->InsertBranch(*NMBB, B, NULL, Cond);