Commit Graph

190 Commits

Author SHA1 Message Date
Jakob Stoklund Olesen
bb30dd40ed Minimize the slot indexes spanned by register ranges created when splitting.
When an interfering live range ends at a dead slot index between two
instructions, make sure that the inserted copy instruction gets a slot index
after the dead ones. This makes it possible to avoid the interference.

Ideally, there shouldn't be interference ending at a deleted instruction, but
physical register coalescing can sometimes do that to sub-registers.

This fixes PR9823.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130687 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-02 05:29:58 +00:00
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
Jakob Stoklund Olesen
cb6404711b Add LiveIntervals::getLastSplitPoint().
A live range cannot be split everywhere in a basic block. A split must go before
the first terminator, and if the variable is live into a landing pad, the split
must happen before the call that can throw.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124894 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-04 19:33:11 +00:00
Jakob Stoklund Olesen
9ecd1e7197 Skip unused values.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124842 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-04 00:59:23 +00:00
Jakob Stoklund Olesen
c50f077b06 Add debug output and asserts to the phi-connecting code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124813 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-03 20:29:39 +00:00
Jakob Stoklund Olesen
08eb8dd616 Fix coloring bug when mapping values in the middle of a live-through block.
If the found value is not live-through the block, we should only add liveness up
to the requested slot index. When the value is live-through, the whole block
should be colored.

Bug found by SSA verification in the machine code verifier.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124812 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-03 20:29:36 +00:00
Jakob Stoklund Olesen
207c868c92 Return live range end points from SplitEditor::enter*/leave*.
These end points come from the inserted copies, and can be passed directly to
useIntv. This simplifies the coloring code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124799 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-03 17:04:16 +00:00
Eric Christopher
0f43811903 Reapply this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124779 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-03 06:18:29 +00:00
Eric Christopher
463a2977b1 Temporarily revert 124765 in an attempt to find the cycle breaking bootstrap.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124778 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-03 05:40:54 +00:00
Jakob Stoklund Olesen
2cd2111959 Defer SplitKit value mapping until all defs are available.
The greedy register allocator revealed some problems with the value mapping in
SplitKit. We would sometimes start mapping values before all defs were known,
and that could change a value from a simple 1-1 mapping to a multi-def mapping
that requires ssa update.

The new approach collects all defs and register assignments first without
filling in any live intervals. Only when finish() is called, do we compute
liveness and mapped values. At this time we know with certainty which values map
to multiple values in a split range.

This also has the advantage that we can compute live ranges based on the
remaining uses after rematerializing at split points.

The current implementation has many opportunities for compile time optimization.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124765 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-03 00:54:23 +00:00
Jakob Stoklund Olesen
078628465b Rename member variables to follow the rest of LLVM.
No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124257 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-26 00:50:53 +00:00
Jakob Stoklund Olesen
d7ca57705e Add LiveIntervalMap::dumpCache() to print out the cache used by the ssa update algorithm.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123925 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-20 17:45:20 +00:00
Jakob Stoklund Olesen
ccdb3fcef9 Implement RAGreedy::splitAroundRegion and remove loop splitting.
Region splitting includes loop splitting as a subset, and it is more generic.
The splitting heuristics for variables that are live in more than one block are
now:

1. Try to create a region that covers multiple basic blocks.
2. Try to create a new live range for each block with multiple uses.
3. Spill.

Steps 2 and 3 are similar to what the standard spiller is doing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123853 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-19 22:11:48 +00:00
Jakob Stoklund Olesen
b5fa933343 Add RAGreedy methods for splitting live ranges around regions.
Analyze the live range's behavior entering and leaving basic blocks. Compute an
interference pattern for each allocation candidate, and use SpillPlacement to
find an optimal region where that register can be live.

This code is still not enabled.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123774 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-18 21:13:27 +00:00
Jakob Stoklund Olesen
8dd070edc2 Turn the EdgeBundles class into a stand-alone machine CFG analysis pass.
The analysis will be needed by both the greedy register allocator and the
X86FloatingPoint pass. It only needs to be computed once when the CFG doesn't
change.

This pass is very fast, usually showing up as 0.0% wall time.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122832 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-04 21:10:05 +00:00
Jakob Stoklund Olesen
c64379da07 Include a shadow of the original CFG edges in the edge bundle graph.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122444 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-22 22:01:28 +00:00
Jakob Stoklund Olesen
8d0963f72c Add EdgeBundles to SplitKit.
Edge bundles is an annotation on the CFG that turns it into a bipartite directed
graph where each basic block is connected to an outgoing and an ingoing bundle.
These bundles are useful for identifying regions of the CFG for live range
splitting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122301 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-21 01:50:21 +00:00
Jakob Stoklund Olesen
dfe3b6d2a9 Check that the register is live-in to the loop header before inserting copies in
the loop predecessors.

The register can be live-out from a predecessor without being live-in to the
loop header if there is a critical edge from the predecessor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122123 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-18 01:06:19 +00:00
Jakob Stoklund Olesen
6203295473 Fix build.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121872 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 18:07:48 +00:00
Jakob Stoklund Olesen
697483addf Detect and enumerate bypass loops.
Bypass loops have the current live range live through, but contain no uses or
defs. Splitting around a bypass loop can free registers for other uses inside
the loop by spilling the split range.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121871 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 17:49:52 +00:00
Jakob Stoklund Olesen
521a453721 Separate SplitAnalysis::getSplitLoops().
This method returns the set of loops with uses that are candidates for
splitting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121870 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15 17:41:19 +00:00
Jakob Stoklund Olesen
b5f327b30f No need to add liveness that's already there.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118742 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-10 23:56:00 +00:00
Jakob Stoklund Olesen
cfa7134a9c Basic rematerialization during splitting.
Whenever splitting wants to insert a copy, it checks if the value can be
rematerialized cheaply instead.

Missing features:
- Delete instructions when all uses have been rematerialized.
- Truncate live ranges to the remaining uses after rematerialization.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118702 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-10 19:31:50 +00:00
Jakob Stoklund Olesen
376dcbd6c2 Tag debug output as regalloc
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118193 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-03 20:39:23 +00:00
Jakob Stoklund Olesen
3d4114c464 When inserting copies during splitting, always use the parent register as the
source, and let rewrite() clean it up.

This way, kill flags on the inserted copies are fixed as well during rewrite().

We can't just assume that all the copies we insert are going to be kills since
critical edges into loop headers sometimes require both source and dest to be
live out of a block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117980 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-01 23:59:48 +00:00
Jakob Stoklund Olesen
79cb53ce95 Update kill flags while rewriting instructions after splitting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117959 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-01 21:51:29 +00:00
Jakob Stoklund Olesen
5b4bb218d1 Make sure copies are inserted after any exception handling labels at the top of
a basic block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117764 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-30 01:26:16 +00:00
Jakob Stoklund Olesen
3ccfce0e35 Don't transfer unused values to the new intervals formed by splitting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117673 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-29 17:47:49 +00:00
Benjamin Kramer
8a8e26fb18 Silence Release build warnings.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117671 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-29 17:40:05 +00:00
Jakob Stoklund Olesen
c94fcb1507 Never propagate the idom value out of a block that defines its own value.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117669 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-29 17:37:25 +00:00
Jakob Stoklund Olesen
e1dde7b05a Replace SplitKit SSA update with an iterative algorithm very similar to the one
in SSAUpdaterImpl.h

Verifying live intervals revealed that the old method was completely wrong, and
we need an iterative approach to calculating PHI placemant. Fortunately, we have
MachineDominators available, so we don't have to compute that over and over
like SSAUpdaterImpl.h must.

Live-out values are cached between calls to mapValue() and computed in a greedy
way, so most calls will be working with very small block sets.

Thanks to Bob for explaining how this should work.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117599 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-28 20:34:52 +00:00
Jakob Stoklund Olesen
d68f458244 Make MachineDominators available for SplitEditor. We are going to need it for
proper SSA updating.

This doesn't cause MachineDominators to be recomputed since we are already
requiring MachineLoopInfo which uses dominators as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117598 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-28 20:34:50 +00:00
Jakob Stoklund Olesen
c95c1465fd Handle critical loop predecessors by making both inside and outside registers
live out.

This doesn't prevent us from inserting a loop preheader later on, if that is
better.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117424 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-27 00:39:07 +00:00
Jakob Stoklund Olesen
0960a650b7 Compute critical loop predecessors in the same way as critical loop exits.
Critical edges going into a loop are not as bad as critical exits. We can handle
them by splitting the critical edge, or by having both inside and outside
registers live out of the predecessor.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117423 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-27 00:39:05 +00:00
Jakob Stoklund Olesen
3a0e0715a5 After splitting, compute connected components of all new registers, not just for
the remainder register.

Example:

bb0:
  x = 1
bb1:
  use(x)
  ...
  x = 2
  jump bb1

When x is isolated in bb1, the inner part breaks into two components, x1 and x2:

bb0:
  x0 = 1
bb1:
  x1 = x0
  use(x1)
  ...
  x2 = 2
  x0 = x2
  jump bb1

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117408 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-26 22:36:09 +00:00
Jakob Stoklund Olesen
f1354ae95a Call RenumberValues for all new registers created during splitting. This is
necessary to get correct hasPHIKill flags.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117406 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-26 22:36:05 +00:00
Jakob Stoklund Olesen
79c0262fa8 Preserve PHIDef bits in cloned values during splitting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117405 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-26 22:36:02 +00:00
Jakob Stoklund Olesen
2bfb324684 Be more strict about detecting multi-use blocks for isolation.
When a block has exactly two uses and the register is both live-in and live-out,
don't isolate the block. We would be inserting two copies, so we haven't really
made any progress.

If the live-in and live-out values separate into disconnected components after
splitting, we would be making progress. We can't detect that for now.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117169 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-22 22:48:56 +00:00
Jakob Stoklund Olesen
2c1442e1b2 Be more strict when detecting critical edges before loop splitting.
An exit block with a critical edge must only have predecessors in the loop, or
just before the loop. This guarantees that the inserted copies in the loop
predecessors dominate the exit block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117144 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-22 20:28:23 +00:00
Jakob Stoklund Olesen
532de3dc6e Add print methods
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117143 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-22 20:28:21 +00:00
Jakob Stoklund Olesen
9d999772df Don't include the destination interval in the union when computing
Parent - union(Y, ...). Doh.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117042 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-21 18:47:08 +00:00
Jakob Stoklund Olesen
9d5d48bc41 Eliminate curli from SplitEditor. Use the LiveRangeEdit reference instead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116547 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-15 00:34:01 +00:00
Jakob Stoklund Olesen
2a0180fbff Move stack slot assignments into LiveRangeEdit.
All registers created during splitting or spilling are assigned to the same
stack slot as the parent register.

When splitting or rematting, we may not spill at all. In that case the stack
slot is still assigned, but it will be dead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116546 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-15 00:16:55 +00:00
Jakob Stoklund Olesen
a17768f582 Create a new LiveRangeEdit class to keep track of the new registers created when
splitting or spillling, and to help with rematerialization.

Use LiveRangeEdit in InlineSpiller and SplitKit. This will eventually make it
possible to share remat code between InlineSpiller and SplitKit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116543 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-14 23:49:52 +00:00
Jakob Stoklund Olesen
ab00e9f498 Only split around a loop if the live range has uses outside the loop periphery.
Before we would also split around a loop if any peripheral block had multiple
uses. This could cause repeated splitting when splitting a different live range
would insert uses into the periphery.

Now -spiller=inline passes the nightly test suite again.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116494 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-14 18:26:45 +00:00
Jakob Stoklund Olesen
7466927b1a Rename SplitEditor::rewrite to finish() and break it out into a couple of new
functions: computeRemainder and rewrite.

When the remainder breaks up into multiple components, remember to rewrite those
uses as well.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116121 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-08 23:42:21 +00:00
Jakob Stoklund Olesen
0253df9a89 After splitting, the remaining LiveInterval may be fragmented into multiple
connected components. These components should be allocated different virtual
registers because there is no reason for them to be allocated together.

Add the ConnectedVNInfoEqClasses class to calculate the connected components,
and move values to new LiveIntervals.

Use it from SplitKit::rewrite by creating new virtual registers for the
components.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@116006 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07 23:34:34 +00:00
Jakob Stoklund Olesen
452a9fdf54 Print more loop info.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115951 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07 18:47:07 +00:00
Jakob Stoklund Olesen
8fc3d1187c Print out MBB number when rewriting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115950 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07 18:47:05 +00:00
Jakob Stoklund Olesen
4b3041c43e Cache interval iterators in SplitEditor::addTruncSimpleRange so we only have to
do one find().

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115929 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07 17:56:39 +00:00
Jakob Stoklund Olesen
9b24afe41e Clean up debug printing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115928 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07 17:56:35 +00:00