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Filter "sink to" candidate blocks sooner. This avoids unnecessary computation to determine whether the block dominates all uses or not.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146184 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Devang Patel 2011-12-08 21:33:23 +00:00
parent 7a7194b529
commit cf405ba7a6
1 changed files with 13 additions and 11 deletions
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24
lib/CodeGen/MachineSink.cpp
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@ -499,10 +499,21 @@ bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) {
// we should sink to.
for (MachineBasicBlock::succ_iterator SI = ParentBlock->succ_begin(),
E = ParentBlock->succ_end(); SI != E; ++SI) {
MachineBasicBlock *SuccBlock = *SI;
// It is not possible to sink an instruction into its own block. This can
// happen with loops.
if (ParentBlock == SuccBlock)
continue;
// It's not safe to sink instructions to EH landing pad. Control flow into
// landing pad is implicitly defined.
if (SuccBlock->isLandingPad())
continue;
bool LocalUse = false;
if (AllUsesDominatedByBlock(Reg, *SI, ParentBlock,
if (AllUsesDominatedByBlock(Reg, SuccBlock, ParentBlock,
BreakPHIEdge, LocalUse)) {
SuccToSinkTo = *SI;
SuccToSinkTo = SuccBlock;
break;
}
if (LocalUse)
@ -520,15 +531,6 @@ bool MachineSinking::SinkInstruction(MachineInstr *MI, bool &SawStore) {
if (SuccToSinkTo == 0)
return false;
// It's not safe to sink instructions to EH landing pad. Control flow into
// landing pad is implicitly defined.
if (SuccToSinkTo->isLandingPad())
return false;
// It is not possible to sink an instruction into its own block. This can
// happen with loops.
if (MI->getParent() == SuccToSinkTo)
return false;
// If the instruction to move defines a dead physical register which is live
// when leaving the basic block, don't move it because it could turn into a