Dead code elimination may separate the live interval into multiple connected components.

I have convinced myself that it can only happen when a phi value dies. When it
happens, allocate new virtual

Dead code elimination may separate the live interval into multiple connected components.

I have convinced myself that it can only happen when a phi value dies. When it
happens, allocate new virtual registers for the components.

llvm-svn: 127827

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Rewrite instructions as part of ConnectedVNInfoEqClasses::Distribute.

llvm-svn: 127779

Preserve both isPHIDef and isDefByCopy bits when copying parent values.

llvm-svn: 127697

Delete dead code after rematerializing.

LiveRangeEdit::eliminateDeadDefs() will eventually be used by coalescing,
splitting, and spilling for dead code elimination. It can delete chains of dead
inst

Delete dead code after rematerializing.

LiveRangeEdit::eliminateDeadDefs() will eventually be used by coalescing,
splitting, and spilling for dead code elimination. It can delete chains of dead
instructions as long as there are no dependency loops.

llvm-svn: 127287

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Work around a coalescer bug.

The coalescer can in very rare cases leave too large live intervals around after
rematerializing cheap-as-a-move instructions.

Linear scan doesn't really care, but live

Work around a coalescer bug.

The coalescer can in very rare cases leave too large live intervals around after
rematerializing cheap-as-a-move instructions.

Linear scan doesn't really care, but live range splitting gets very confused
when a live range is killed by a ghost instruction.

I will fix this properly in the coalescer after 2.9 branches.

llvm-svn: 127096

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Tweak debug output. No functional changes.

llvm-svn: 127006

Use an IndexedMap instead of a DenseMap for the live-out cache.

This speeds up updateSSA() so it only accounts for 5% of the live range
splitting time.

llvm-svn: 126972

Cache basic block bounds instead of asking SlotIndexes::getMBBRange all the time.

This speeds up the greedy register allocator by 15%.
DenseMap is not as fast as one might hope.

llvm-svn: 126921

Change the SplitEditor interface to a single instance can be shared for multiple splits.

llvm-svn: 126912

Only run the updateSSA loop when we have actually seen multiple values.

When only a single value has been seen, new PHIDefs are never needed.

llvm-svn: 126911

Turn the Edit member into a pointer so it can change dynamically.

No functional change.

llvm-svn: 126898

Transfer simply defined values directly without recomputing liveness and SSA.

Values that map to a single new value in a new interval after splitting don't
need new PHIDefs, and if the parent value

Transfer simply defined values directly without recomputing liveness and SSA.

Values that map to a single new value in a new interval after splitting don't
need new PHIDefs, and if the parent value was never rematerialized the live
range will be the same.

llvm-svn: 126894

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Extract a method. No functional change.

llvm-svn: 126893

Move extendRange() into SplitEditor and delete the LiveRangeMap class.

Extract the updateSSA() method from the too long extendRange().

LiveOutCache can be shared among all the new intervals since t

Move extendRange() into SplitEditor and delete the LiveRangeMap class.

Extract the updateSSA() method from the too long extendRange().

LiveOutCache can be shared among all the new intervals since there is at most
one of the new ranges live out from each basic block.

llvm-svn: 126818

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Rename mapValue to extendRange because that is its function now.

Simplify the signature - The return value and ParentVNI are no longer needed.

llvm-svn: 126809

Move LiveIntervalMap::extendTo into LiveInterval itself.

This method could probably be used by LiveIntervalAnalysis::shrinkToUses, and
now it can use extendIntervalEndTo() which coalesces ranges.

l

Move LiveIntervalMap::extendTo into LiveInterval itself.

This method could probably be used by LiveIntervalAnalysis::shrinkToUses, and
now it can use extendIntervalEndTo() which coalesces ranges.

llvm-svn: 126803

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Delete dead code.

llvm-svn: 126801

Move the value map from LiveIntervalMap to SplitEditor.

The value map is currently not used, all values are 'complex mapped' and
LiveIntervalMap::mapValue is used to dig them out.

This is the first

Move the value map from LiveIntervalMap to SplitEditor.

The value map is currently not used, all values are 'complex mapped' and
LiveIntervalMap::mapValue is used to dig them out.

This is the first step in a series changes leading to the removal of
LiveIntervalMap. Its data structures can be shared among all the live intervals
created by a split, so it is wasteful to create a copy for each.

llvm-svn: 126800

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Delete dead code.

Local live range splitting is better driven by interference. This code was just
guessing.

llvm-svn: 126799

It is safe to ignore LastSplitPoint when the variable is not live out.

No code will be inserted after the split point anyway.

llvm-svn: 126319

Add SplitKit::isOriginalEndpoint and use it to force live range splitting to terminate.

An original endpoint is an instruction that killed or defined the original live
range before any live ranges w

Add SplitKit::isOriginalEndpoint and use it to force live range splitting to terminate.

An original endpoint is an instruction that killed or defined the original live
range before any live ranges were split.

When splitting global live ranges, avoid creating local live ranges without any
original endpoints. We may still create global live ranges without original
endpoints, but such a range won't be split again, and live range splitting still
terminates.

llvm-svn: 126151

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Give SplitAnalysis a VRM member to access VirtRegMap::getOriginal().

llvm-svn: 126005

Missed member rename for naming convention.

llvm-svn: 126003

Delete unused code for analyzing and splitting around loops.

Loop splitting is better handled by the more generic global region splitting
based on the edge bundle graph.

llvm-svn: 125243

Use the LiveBLocks array for SplitEditor::splitSingleBlocks() as well.

This fixes a bug where splitSingleBlocks() could split a live range after a
terminator instruction.

llvm-svn: 125237