Commit Graph

164 Commits

Author SHA1 Message Date
Jakob Stoklund Olesen
75e28f74b0 Delete getMultiUseBlocks and splitSingleBlocks.
These functions are no longer used, and they are easily replaced with a
loop calling shouldSplitSingleBlock and splitSingleBlock.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136993 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-05 22:52:17 +00:00
Jakob Stoklund Olesen
2d6d86be84 Split around single instructions to enable register class inflation.
Normally, we don't create a live range for a single instruction in a
basic block, the spiller does that anyway. However, when splitting a
live range that belongs to a proper register sub-class, inserting these
extra COPY instructions completely remove the constraints from the
remainder interval, and it may be allocated from the larger super-class.

The spiller will mop up these small live ranges if we end up spilling
anyway. It calls them snippets.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136989 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-05 22:20:45 +00:00
Jakob Stoklund Olesen
fe62d92b7b Rename {First,Last}Use to {First,Last}Instr.
With a 'FirstDef' field right there, it is very confusing that FirstUse
refers to an instruction that may be a def.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136739 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-02 22:54:14 +00:00
Jakob Stoklund Olesen
77ee1140a3 Add a BlockInfo::FirstDef field.
This is either an invalid SlotIndex, or valno->def for the first value
defined inside the block. PHI values are not counted as defined inside
the block.

The FirstDef field will be used when estimating the cost of spilling
around a block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136736 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-02 22:37:22 +00:00
Jakob Stoklund Olesen
4751eb760e Delete BlockInfo::LiveThrough. It wasn't used any more.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136735 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-02 22:37:20 +00:00
Jakob Stoklund Olesen
81d686edbe Never extend live ranges for <undef> uses.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135886 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-24 20:33:23 +00:00
Jakob Stoklund Olesen
b09701db9e Correctly handle <undef> tied uses when rewriting after a split.
This fixes PR10463. A two-address instruction with an <undef> use
operand was incorrectly rewritten so the def and use no longer used the
same register, violating the tie constraint.

Fix this by always rewriting <undef> operands with the register a def
operand would use.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135885 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-24 20:23:50 +00:00
Jakob Stoklund Olesen
fe9b2d142a Fix bug in SplitEditor::splitLiveThroughBlock when switching registers.
If there is no interference and no last split point, we cannot
enterIntvBefore(Stop) - that function needs a real instruction.

Use enterIntvAtEnd instead for that very easy case.

This code doesn't currently run, it is needed by multi-way splitting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135846 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-23 03:32:26 +00:00
Jakob Stoklund Olesen
fc47933db5 Fix a crash when building 177.mesa for armv6.
When splitting a live range immediately before an LDR_POST instruction
that redefines the address register, make sure to use the correct value
number in leaveIntvBefore.

We need the value number entering the instruction.

<rdar://problem/9793765>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135413 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-18 18:47:13 +00:00
Matt Beaumont-Gay
f9d7fb6b3c Silence unused variable warning
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135339 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-16 04:18:47 +00:00
Jakob Stoklund Olesen
af4e40c2f4 He said *before* the last split point.
This should unbreak the build-self-4-mingw32 tester. I have a very
complicated test case that I will try to clean up.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135329 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-16 00:13:30 +00:00
Jakob Stoklund Olesen
b4ddedce59 Extract parts of RAGreedy::splitAroundRegion as SplitKit methods.
This gets rid of some of the gory splitting details in RAGreedy and
makes them available to future SplitKit clients.

Slightly generalize the functionality to support multi-way splitting.
Specifically, SplitEditor::splitLiveThroughBlock() supports switching
between different register intervals in a block.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135307 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-15 21:47:57 +00:00
Jakob Stoklund Olesen
87360f73ae Reapply r134047 now that the world is ready for it.
This patch will sometimes choose live range split points next to
interference instead of always splitting next to a register point. That
means spill code can now appear almost anywhere, and it was necessary
to fix code that didn't expect that.

The difficult places were:

- Between a CALL returning a value on the x87 stack and the
  corresponding FpPOP_RETVAL (was FpGET_ST0). Probably also near x87
  inline assembly, but that didn't actually show up in testing.

- Between a CALL popping arguments off the stack and the corresponding
  ADJCALLSTACKUP.

Both are fixed now. The only place spill code can't appear is after
terminators, see SplitAnalysis::getLastSplitPoint.

Original commit message:

Rewrite RAGreedy::splitAroundRegion, now with cool ASCII art.

This function has to deal with a lot of special cases, and the old
version got it wrong sometimes. In particular, it would sometimes leave
multiple uses in the stack interval in a single block. That causes bad
code with multiple reloads in the same basic block.

The new version handles block entry and exit in a single pass. It first
eliminates all the easy cases, and then goes on to create a local
interval for the blocks with difficult interference. Previously, we
would only create the local interval for completely isolated blocks.

It can happen that the stack interval becomes completely empty because
we could allocate a register in all edge bundles, and the new local
intervals deal with the interference. The empty stack interval is
harmless, but we need to remove a SplitKit assertion that checks for
empty intervals.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134125 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-30 01:30:39 +00:00
Jakob Stoklund Olesen
2c0cbce763 Revert r134047 while investigating a llvm-gcc-i386-linux-selfhost
miscompile.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134053 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-29 02:03:36 +00:00
Jakob Stoklund Olesen
4d517e34e5 Rewrite RAGreedy::splitAroundRegion, now with cool ASCII art.
This function has to deal with a lot of special cases, and the old
version got it wrong sometimes. In particular, it would sometimes leave
multiple uses in the stack interval in a single block. That causes bad
code with multiple reloads in the same basic block.

The new version handles block entry and exit in a single pass. It first
eliminates all the easy cases, and then goes on to create a local
interval for the blocks with difficult interference. Previously, we
would only create the local interval for completely isolated blocks.

It can happen that the stack interval becomes completely empty because
we could allocate a register in all edge bundles, and the new local
intervals deal with the interference. The empty stack interval is
harmless, but we need to remove a SplitKit assertion that checks for
empty intervals.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134047 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-29 00:24:24 +00:00
Jakob Stoklund Olesen
1e0bd63477 Fix a bad iterator dereference that Evan uncovered.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133978 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-28 01:18:58 +00:00
Rafael Espindola
5b220213bf There is only one register coalescer. Merge it into the base class and
remove the analysis group.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133899 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-26 22:34:10 +00:00
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
bdda37d7fb Fix PR9883. Make sure all caches are invalidated when a live range is repaired.
The previous invalidation missed the alias interference caches.

Also add a stats counter for the number of repaired ranges.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131133 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-10 17:37:41 +00:00
Jakob Stoklund Olesen
e9bd4ea5fd Add some statistics to the splitting and spilling frameworks.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130931 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-05 17:22:53 +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
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