Commit Graph

139 Commits

Author SHA1 Message Date
Jakob Stoklund Olesen
9f4b893b84 Add a safe-guard against repeated splitting for some rare cases.
The number of blocks covered by a live range must be strictly decreasing when
splitting, otherwise we can't allow repeated splitting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130249 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-26 22:33:12 +00:00
Matt Beaumont-Gay
ae5fbeec23 Don't recycle loop variables.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129928 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-21 19:46:23 +00:00
Jakob Stoklund Olesen
5928046306 Allow allocatable ranges from global live range splitting to be split again.
These intervals are allocatable immediately after splitting, but they may be
evicted because of later splitting. This is rare, but when it happens they
should be split again.

The remainder intervals that cannot be allocated after splitting still move
directly to spilling.

SplitEditor::finish can optionally provide a mapping from new live intervals
back to the original interval indexes returned by openIntv().

Each original interval index can map to multiple new intervals after connected
components have been separated. Dead code elimination may also add existing
intervals to the list.

The reverse mapping allows the SplitEditor client to treat the new intervals
differently depending on the split region they came from.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129925 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-21 18:38:15 +00:00
Francois Pichet
cbc5f407ef Unbreak the MSVC 2010 build.
For further information on this particular issue see: http://connect.microsoft.com/VisualStudio/feedback/details/520043/error-converting-from-null-to-a-pointer-type-in-std-pair

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129642 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-16 14:20:39 +00:00
Jakob Stoklund Olesen
44b7ae2355 Teach the SplitKit blitter to handle multiply defined values as well.
The transferValues() function can now handle both singly and multiply defined
values, as long as the resulting live range is known. Only rematerialized values
have their live range recomputed by extendRange().

The updateSSA() function can now insert PHI values in bulk across multiple
values in multiple target registers in one pass. The list of blocks received
from transferValues() is in layout order which seems to work well for the
iterative algorithm. Blocks from extendRange() are still in reverse BFS order,
but this function is used so rarely now that it doesn't matter.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129580 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-15 17:24:49 +00:00
Jakob Stoklund Olesen
fd1cced726 Stop using dead function.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129442 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-13 15:00:11 +00:00
Jakob Stoklund Olesen
fd5c51342a Create new intervals for isolated blocks during region splitting.
This merges the behavior of splitSingleBlocks into splitAroundRegion, so the
RS_Region and RS_Block register stages can be coalesced. That means the leftover
intervals after region splitting go directly to spilling instead of a second
pass of per-block splitting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129379 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-12 19:32:53 +00:00
Jakob Stoklund Olesen
e1b43c3b40 Add SplitKit API to query and select the current interval being worked on.
This makes it possible to target multiple registers in one pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129374 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-12 18:11:31 +00:00
Jakob Stoklund Olesen
f4afdfc501 Build the Hopfield network incrementally when splitting global live ranges.
It is common for large live ranges to have few basic blocks with register uses
and many live-through blocks without any uses. This approach grows the Hopfield
network incrementally around the use blocks, completely avoiding checking
interference for some through blocks.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129188 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-09 02:59:09 +00:00
Jakob Stoklund Olesen
db529a8a5d Analyze blocks with uses separately from live-through blocks without uses.
About 90% of the relevant blocks are live-through without uses, and the only
information required about them is their number. This saves memory and enables
later optimizations that need to look at only the use-blocks.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128985 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-06 03:57:00 +00:00
Jakob Stoklund Olesen
71d9e65ee7 Sign error
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128963 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-05 23:43:16 +00:00
Jakob Stoklund Olesen
b3dd82670a Don't crash when a value is defined after the last split point.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128962 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-05 23:43:14 +00:00
Jakob Stoklund Olesen
a2948ef5ac Use std::unique instead of a SmallPtrSet to ensure unique instructions in UseSlots.
This allows us to always keep the smaller slot for an instruction which is what
we want when a register has early clobber defines.

Drop the UsingInstrs set and the UsingBlocks map. They are no longer needed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128886 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-05 15:18:18 +00:00
Jakob Stoklund Olesen
612f7807c5 Stop precomputing last split points, query the SplitAnalysis cache on demand.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128875 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-05 04:20:29 +00:00
Jakob Stoklund Olesen
1a7744501a Cache the fairly expensive last split point computation and provide a fast
inlined path for the common case.

Most basic blocks don't contain a call that may throw, so the last split point
os simply the first terminator.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128874 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-05 04:20:27 +00:00
Jakob Stoklund Olesen
6c8afd728e Stop caching basic block index ranges now that SlotIndexes can keep up.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128821 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-04 15:32:15 +00:00
Jakob Stoklund Olesen
6094bd87d8 Recompute register class and hint for registers created during spilling.
The spill weight is not recomputed for an unspillable register - it stays infinite.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128490 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-29 21:20:19 +00:00
Jakob Stoklund Olesen
c8ec765551 Handle the special case when all uses follow the last split point.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128450 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-29 03:12:04 +00:00
Jakob Stoklund Olesen
ef1f5ccca7 Amend debug output.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128398 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-27 22:49:23 +00:00
Jakob Stoklund Olesen
2dc455a366 Process all dead defs after rematerializing during splitting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127973 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-20 19:46:23 +00:00
Jakob Stoklund Olesen
7cec179a64 Be more accurate about the slot index reading a register when dealing with defs
and early clobbers.

Assert when trying to find an undefined value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127856 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-18 03:06:02 +00:00
Jakob Stoklund Olesen
6a3dbd3b25 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127827 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-17 20:37:07 +00:00
Jakob Stoklund Olesen
2254227791 Rewrite instructions as part of ConnectedVNInfoEqClasses::Distribute.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127779 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-17 00:23:45 +00:00
Jakob Stoklund Olesen
29ef87599c Preserve both isPHIDef and isDefByCopy bits when copying parent values.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127697 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-15 21:13:22 +00:00
Jakob Stoklund Olesen
5881799d0c 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127287 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-08 22:46:11 +00:00
Jakob Stoklund Olesen
2b0f9e73d8 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127096 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-05 18:33:49 +00:00
Jakob Stoklund Olesen
fb69810a2b Tweak debug output. No functional changes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127006 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-04 18:08:26 +00:00
Jakob Stoklund Olesen
13ba2dab63 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126972 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-04 00:15:36 +00:00
Jakob Stoklund Olesen
36d61863bc 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126921 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-03 03:41:29 +00:00
Jakob Stoklund Olesen
bece06f0c6 Change the SplitEditor interface to a single instance can be shared for multiple splits.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126912 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-03 01:29:13 +00:00
Jakob Stoklund Olesen
8701768ae2 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126911 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-03 01:29:10 +00:00
Jakob Stoklund Olesen
a2cae58411 Turn the Edit member into a pointer so it can change dynamically.
No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126898 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-02 23:31:50 +00:00
Jakob Stoklund Olesen
4670353a21 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126894 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-02 23:05:19 +00:00
Jakob Stoklund Olesen
e2dc0c978e Extract a method. No functional change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126893 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-02 23:05:16 +00:00
Jakob Stoklund Olesen
1c38ba6355 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126818 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-02 01:59:34 +00:00
Jakob Stoklund Olesen
d3fdaeb69a Rename mapValue to extendRange because that is its function now.
Simplify the signature - The return value and ParentVNI are no longer needed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126809 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-02 00:49:28 +00:00
Jakob Stoklund Olesen
9763e2bf39 Move LiveIntervalMap::extendTo into LiveInterval itself.
This method could probably be used by LiveIntervalAnalysis::shrinkToUses, and
now it can use extendIntervalEndTo() which coalesces ranges.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126803 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-02 00:06:15 +00:00
Jakob Stoklund Olesen
edb87555e4 Delete dead code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126801 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-01 23:24:19 +00:00
Jakob Stoklund Olesen
670ccd18ae 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126800 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-01 23:14:53 +00:00
Jakob Stoklund Olesen
3afab9c57e Delete dead code.
Local live range splitting is better driven by interference. This code was just
guessing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126799 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-01 23:14:50 +00:00
Jakob Stoklund Olesen
c70f687dce It is safe to ignore LastSplitPoint when the variable is not live out.
No code will be inserted after the split point anyway.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126319 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-23 18:26:31 +00:00
Jakob Stoklund Olesen
06c0f25499 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126151 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-21 23:09:46 +00:00
Jakob Stoklund Olesen
1b847deb26 Give SplitAnalysis a VRM member to access VirtRegMap::getOriginal().
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126005 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-19 00:53:42 +00:00
Jakob Stoklund Olesen
0eeca44046 Missed member rename for naming convention.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126003 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-19 00:42:33 +00:00
Jakob Stoklund Olesen
4f5c9d2061 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125243 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-09 23:56:18 +00:00
Jakob Stoklund Olesen
9b057771ba Use the LiveBLocks array for SplitEditor::splitSingleBlocks() as well.
This fixes a bug where splitSingleBlocks() could split a live range after a
terminator instruction.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125237 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-09 23:30:25 +00:00
Jakob Stoklund Olesen
f0ac26c511 Move calcLiveBlockInfo() and the BlockInfo struct into SplitAnalysis.
No functional changes intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125231 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-09 22:50:26 +00:00
Jakob Stoklund Olesen
a372d16f92 Ignore <undef> uses when analyzing and rewriting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125226 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-09 21:52:09 +00:00
Jakob Stoklund Olesen
5c716bdccc Add SplitEditor::overlapIntv() to create small ranges where both registers are live.
If a live range is used by a terminator instruction, and that live range needs
to leave the block on the stack or in a different register, it can be necessary
to have both sides of the split live at the terminator instruction.

Example:

  %vreg2 = COPY %vreg1
  JMP %vreg1

Becomes after spilling %vreg2:

  SPILL %vreg1
  JMP %vreg1

The spill doesn't kill the register as is normally the case.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125102 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-08 18:50:21 +00:00
Jakob Stoklund Olesen
01cb34b011 Add assertion.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125101 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-08 18:50:18 +00:00