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Fix PR10277.

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Remat during spilling triggers dead code elimination. If a phi-def
becomes unused, that may also cause live ranges to split into separate
connected components.

This type of splitting is different from normal live range splitting. In
particular, there may not be a common original interval.

When the split range is its own original, make sure that the new
siblings are also their own originals. The range being split cannot be
used as an original since it doesn't cover the new siblings.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134413 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen
2011-07-05 15:38:41 +00:00
parent 2b0f4abfbe
commit 9693d4c3f0
3 changed files with 108 additions and 0 deletions
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6
lib/CodeGen/LiveRangeEdit.cpp
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@@ -298,10 +298,16 @@ void LiveRangeEdit::eliminateDeadDefs(SmallVectorImpl<MachineInstr*> &Dead,
if (NumComp <= 1)
continue;
++NumFracRanges;
bool IsOriginal = VRM.getOriginal(LI->reg) == LI->reg;
DEBUG(dbgs() << NumComp << " components: " << *LI << '\n');
SmallVector<LiveInterval*, 8> Dups(1, LI);
for (unsigned i = 1; i != NumComp; ++i) {
Dups.push_back(&createFrom(LI->reg, LIS, VRM));
// If LI is an original interval that hasn't been split yet, make the new
// intervals their own originals instead of referring to LI. The original
// interval must contain all the split products, and LI doesn't.
if (IsOriginal)
VRM.setIsSplitFromReg(Dups.back()->reg, 0);
if (delegate_)
delegate_->LRE_DidCloneVirtReg(Dups.back()->reg, LI->reg);
}