Commit Graph

87 Commits

Author SHA1 Message Date
Jakob Stoklund Olesen
a2e79ef908 Reapply r132245 with a fix for the bug that broke the darwin9/i386 build.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132309 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-30 01:33:26 +00:00
Jakob Stoklund Olesen
626d6fb190 Revert r132245, "Create two BlockInfo entries when a live range is discontinuous through a block."
This commit seems to have broken a darwin 9 tester.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132299 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-29 21:24:39 +00:00
Jakob Stoklund Olesen
c9cf9e94ec Create two BlockInfo entries when a live range is discontinuous through a block.
Delete the Kill and Def markers in BlockInfo. They are no longer
necessary when BlockInfo describes a continuous live range.

This only affects the relatively rare kind of basic block where a live
range looks like this:

 |---x   o---|

Now live range splitting can pretend that it is looking at two blocks:

 |---x
         o---|

This allows the code to be simplified a bit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132245 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-28 02:33:00 +00:00
Jakob Stoklund Olesen
b2abfa0bf3 Add SplitAnalysis::getNumLiveBlocks().
It is important that this function returns the same number of live blocks as
countLiveBlocks(CurLI) because live range splitting uses the number of live
blocks to ensure it is making progress.

This is in preparation of supporting duplicate UseBlock entries for basic blocks
that have a virtual register live-in and live-out, but not live-though.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132244 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-28 02:32:57 +00:00
Jakob Stoklund Olesen
7d6b6a05b5 Gracefully handle invalid live ranges. Fix PR9831.
Register coalescing can sometimes create live ranges that end in the middle of a
basic block without any killing instruction. When SplitKit detects this, it will
repair the live range by shrinking it to its uses.

Live range splitting also needs to know about this. When the range shrinks so
much that it becomes allocatable, live range splitting fails because it can't
find a good split point. It is paranoid about making progress, so an allocatable
range is considered an error.

The coalescer should really not be creating these bad live ranges. They appear
when coalescing dead copies.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130787 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-03 20:42:13 +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
Sebastian Redl
6796e4fc88 Give SplitKit.h a header guard.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130095 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-24 15:46:51 +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
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
5db4289e40 SparseBitVector is SLOW.
Use a Bitvector instead, we didn't need the smaller memory footprint anyway.
This makes the greedy register allocator 10% faster.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129390 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-12 21:30:53 +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
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
5c4c4d4b82 Delete leftover data members.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128820 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-04 15:32:11 +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
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
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
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
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
034a80d065 Split local live ranges.
A local live range is live in a single basic block. If such a range fails to
allocate, try to find a sub-range that would get a larger spill weight than its
interference.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125764 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17 19:13:53 +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
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
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
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