Commit Graph

165 Commits

Author SHA1 Message Date
Benjamin Kramer
a67f14bf53 Make a bunch of symbols private.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138025 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-19 01:42:18 +00:00
Jakob Stoklund Olesen
27215676c7 Refer to the RegisterCoalescer pass by ID.
A public interface is no longer needed since RegisterCoalescer is not an
analysis any more.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137082 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-09 00:29:53 +00:00
Jakob Stoklund Olesen
69145baf36 Fix typo. Thanks, Andy!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137023 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-06 18:20:24 +00:00
Jakob Stoklund Olesen
ccfa446450 Reject RS_Spill ranges from local splitting as well.
All new local ranges are marked as RS_New now, so there is no need to
attempt splitting of RS_Spill ranges any more.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137002 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-05 23:50:33 +00:00
Jakob Stoklund Olesen
a9c41d39d1 Only mark remainder intervals as RS_Spill after per-block splitting.
The local ranges created get to stay in the RS_New stage, just like for
local and region splitting.

This gives tryLocalSplit a bit more freedom the first time it sees one
of these new local ranges.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137001 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-05 23:50:31 +00:00
Jakob Stoklund Olesen
1f8804263f Remember to update LiveDebugVariables after per-block splitting.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136996 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-05 23:10:40 +00:00
Jakob Stoklund Olesen
dab35d33ae Extract per-block splitting into its own method.
No functional change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136994 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-05 23:04:18 +00:00
Jakob Stoklund Olesen
b3ef7f6b97 Also use shouldSplitSingleBlock() in the fallback splitting mode.
Drop the use of SplitAnalysis::getMultiUseBlocks, there is no need to go
through a SmallPtrSet any more.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136992 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-05 22:43:23 +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
a92afc18a8 Enable compact region splitting by default.
This helps generate better code in functions with high register
pressure.

The previous version of compact region splitting caused regressions
because the regions were a bit too large. A stronger negative bias
applied in r136832 fixed this problem.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136836 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-03 23:16:09 +00:00
Jakob Stoklund Olesen
b87f91b063 Be more conservative when forming compact regions.
Apply twice the negative bias on transparent blocks when computing the
compact regions. This excludes loop backedges from the region when only
one of the loop blocks uses the register.

Previously, we would include the backedge in the region if the loop
preheader and the loop latch both used the register, but the loop header
didn't.

When both the header and latch blocks use the register, we still keep it
live on the backedge.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136832 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-03 23:09:38 +00:00
Chandler Carruth
32668ea7a2 Fix some warnings from Clang in release builds:
lib/CodeGen/RegAllocGreedy.cpp:1176:18: warning: unused variable 'B' [-Wunused-variable]
    if (unsigned B = Cand.getBundles(BundleCand, BestCand)) {
                 ^
lib/CodeGen/RegAllocGreedy.cpp:1188:18: warning: unused variable 'B' [-Wunused-variable]
    if (unsigned B = Cand.getBundles(BundleCand, 0)) {
                 ^

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136831 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-03 23:07:27 +00:00
Jakob Stoklund Olesen
3f5beede1b Use the precomputed def presence in RAGreedy::calcSpillCost.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136742 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-02 23:04:08 +00:00
Jakob Stoklund Olesen
5ebca793db Inform SpillPlacement about blocks with defs.
This information is not used for anything yet.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136741 91177308-0d34-0410-b5e6-96231b3b80d8
2011-08-02 23:04:06 +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
c47690264a Time the emission of debug values.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136584 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-31 03:53:42 +00:00
Jakob Stoklund Olesen
21384c4ea8 Revert r136528 "Enable compact region splitting by default."
While this generally helped x86-64, there was some large regressions
for i386.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136571 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-30 17:19:14 +00:00
Jakob Stoklund Olesen
9162abb39f Enable compact region splitting by default.
This helps generate better code in functions with high register
pressure.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136528 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-29 22:10:27 +00:00
Jakob Stoklund Olesen
cc07e04262 Reverse order of RS_Split live ranges under -compact-regions.
There are two conflicting strategies in play:

- Under high register pressure, we want to assign large live ranges
  first. Smaller live ranges are easier to place afterwards.

- Live range splitting is guided by interference, so splitting should be
  deferred until interference is as realistic as possible.

With the recent changes to the live range stages, and with compact
regions enabled, it is less traumatic to split a live range too early.
If some of the split products were too big, they can often be split
again.

By reversing the RS_Split order, we get this queue order:

1. Normal live ranges, large to small.
2. RS_Split live ranges, large to small.

The large-to-small order improves RAGreedy's puzzle solving skills under
high register pressure. It may cause a bit more iterated splitting, but
we handle that better now.

With this change, -compact-regions is mostly an improvement on SPEC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136388 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-28 20:48:23 +00:00
Jakob Stoklund Olesen
00005782fa Add support for multi-way live range splitting.
When splitting global live ranges, it is now possible to split for
multiple destination intervals at once. Previously, we only had the main
and stack intervals.

Each edge bundle is assigned to a split candidate, and splitAroundRegion
will insert copies between the candidate intervals and the stack
interval as needed.

The multi-way splitting is used to split around compact regions when
enabled with -compact-regions. The best candidate register still gets
all the bundles it wants, but everything outside the main interval is
first split around compact regions before we create single-block
intervals.

Compact region splitting still causes some regressions, so it is not
enabled by default.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136186 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-26 23:41:46 +00:00
Jakob Stoklund Olesen
165e231c42 Revert to RA_Assign when a virtreg separates into components.
When dead code elimination deletes a PHI value, the virtual register may
split into multiple connected components. In that case, revert each
component to the RS_Assign stage.

The new components are guaranteed to be smaller (the original value
numbers are distributed among the components), so this will always be
making progress. The components are now allowed to evict other live
ranges or be split again.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136034 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-26 00:54:56 +00:00
Jakob Stoklund Olesen
49743b18f5 Add an RS_Split2 stage used for loop prevention.
This mechanism already exists, but the RS_Split2 stage makes it clearer.

When live range splitting creates ranges that may not be making
progress, they are marked RS_Split2 instead of RS_New. These ranges may
be split again, but only in a way that can be proven to make progress.

For local ranges, that means they must be split into ranges used by
strictly fewer instructions.

For global ranges, region splitting is bypassed and the RS_Split2
ranges go straight to per-block splitting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135912 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-25 15:25:43 +00:00
Jakob Stoklund Olesen
fa89a0344b Rename live range stages to better reflect how they are used.
The stage is used to control where a live range is going, not where it
is coming from. Live ranges created by splitting will usually be marked
RS_New, but some are marked RS_Spill to avoid wasting time trying to
split them again.

The old RS_Global and RS_Local stages are merged - they are really the
same thing for local and global live ranges.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135911 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-25 15:25:41 +00:00
Jakob Stoklund Olesen
87972fa63f Add RAGreedy::calcCompactRegion.
This method computes the edge bundles that should be live when splitting
around a compact region. This is independent of interference.

The function returns false if the live range was already a compact
region, or the compact region doesn't have any live bundles - it would
be the same as splitting around basic blocks.

Compact regions are computed using the normal spill placement code. We
pretend there is interference in all live-through blocks that don't use
the live range. This removes all edges from the Hopfield network used
for spill placement, so it converges instantly.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135847 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-23 03:41:57 +00:00
Jakob Stoklund Olesen
b4666364f4 Prepare RAGreedy::growRegion for compact regions.
A split candidate can have a null PhysReg which means that it doesn't
map to a real interference pattern. Instead, pretend that all through
blocks have interference.

This makes it possible to generate compact regions where the live range
doesn't go through blocks that don't use it. The live range will still
be live between directly connected blocks with uses.

Splitting around a compact region tends to produce a live range with a
high spill weight, so it may evict a less dense live range.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135845 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-23 03:22:33 +00:00
Frits van Bommel
39b5abf507 Migrate LLVM and Clang to use the new makeArrayRef(...) functions where previously explicit non-default constructors were used.
Mostly mechanical with some manual reformatting.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135390 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-18 12:00:32 +00:00
Jakub Staszak
975eb99cf3 Remove unused LoopRanges from RegAllocGreedy.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135354 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-16 20:43:00 +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
f1c709837b Reapply r135121 with a fixed copy constructor.
Original commit message:

Count references to interference cache entries.

Each InterferenceCache::Cursor instance references a cache entry. A
non-zero reference count guarantees that the entry won't be reused for a
new register.

This makes it possible to have multiple live cursors examining
interference for different physregs.

The total number of live cursors into a cache must be kept below
InterferenceCache::getMaxCursors().

Code generation should be unaffected by this change, and it doesn't seem
to affect the cache replacement strategy either.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135130 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-14 05:35:11 +00:00
Jakob Stoklund Olesen
4fcfcf4984 Revert r135121 which broke a gcc-4.2 builder.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135122 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-14 00:58:38 +00:00
Jakob Stoklund Olesen
6a9feaac93 Count references to interference cache entries.
Each InterferenceCache::Cursor instance references a cache entry. A
non-zero reference count guarantees that the entry won't be reused for a
new register.

This makes it possible to have multiple live cursors examining
interference for different physregs.

The total number of live cursors into a cache must be kept below
InterferenceCache::getMaxCursors().

Code generation should be unaffected by this change, and it doesn't seem
to affect the cache replacement strategy either.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135121 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-14 00:31:14 +00:00
Jakob Stoklund Olesen
c66a37df73 Reapply r135074 and r135080 with a fix.
The cache entry referenced by the best split candidate could become
clobbered by an unsuccessful candidate.

The correct fix here is to use reference counts on the cache entries.
Coming up.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135113 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-14 00:17:10 +00:00
Jakob Stoklund Olesen
54c74e906a Revert r135074 and r135080. They broke clamscan.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135096 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-13 22:20:09 +00:00
Jakob Stoklund Olesen
3bae1bf62e Only keep the global split candidates that work out.
Some pysical registers create split solutions that would spill anywhere.
They should not even be considered in future multi-way global splits.

This does not affect code generation (yet).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135080 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-13 20:49:46 +00:00
Jakob Stoklund Olesen
1337e2b75a Move the InterferenceCache cursor into the GlobalSplitCand struct.
This is in preparation of supporting multiple global split candidates in
a single live range split operation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135074 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-13 20:14:52 +00:00
Jakob Stoklund Olesen
51458ed09e Be more aggressive about following hints.
RAGreedy::tryAssign will now evict interference from the preferred
register even when another register is free.

To support this, add the EvictionCost struct that counts how many hints
are broken by an eviction. We don't want to break one hint just to
satisfy another.

Rename canEvict to shouldEvict, and add the first bit of eviction policy
that doesn't depend on spill weights: Always make room in the preferred
register as long as the evictees can be split and aren't already
assigned to their preferred register.

Also make the CSR avoidance more accurate. When looking for a cheaper
register it is OK to use a new volatile register. Only CSR aliases that
have never been used before should be avoided.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134735 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-08 20:46:18 +00:00
Jakob Stoklund Olesen
549019792a Break infinite loop when the Hopfield network oscillates.
This is impossible in theory, I can prove it. In practice, our near-zero
threshold can cause the network to oscillate between equally good
solutions.

<rdar://problem/9720596>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134428 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-05 18:46:42 +00:00
Jakob Stoklund Olesen
2b0f4abfbe Tweak comment and debug output.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134412 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-05 15:38:37 +00:00
Jakob Stoklund Olesen
736a0118b5 Fix PR10244.
A split point inserted in a block with a landing pad successor may be
hoisted above the call to ensure that it dominates all successors. The
code that handles the rest of the basic block must take this into
account.

I am not including a test case, it would be very fragile. PR10244 comes
from building clang with exceptions enabled.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134369 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-04 00:05:28 +00:00
Jakob Stoklund Olesen
1a988004db Use a new strategy for preventing eviction loops in RAGreedy.
Every live range is assigned a cascade number the first time it is
involved in an eviction. As the evictor, it gets a new cascade number.
Every evictee is assigned the same cascade number as the evictor.

Eviction is prohibited if the evictor has a lower assigned cascade
number than the evictee.

This means that assigned cascade numbers are monotonically increasing
with every eviction, yet they are bounded by NextCascade which can only
be incremented by new live ranges. Thus, infinite loops cannot happen,
but eviction cascades can still be triggered by new live ranges as we
want.

Thanks to Andy for explaining this to me.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134303 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-02 01:37:09 +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
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
Rafael Espindola
fdf16ca44f Move RegisterCoalescer.h to lib/CodeGen.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133895 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-26 21:41:06 +00:00
Jakob Stoklund Olesen
b3e705f889 Simplify local live range splitting's safeguard to fix PR10070.
When local live range splitting creates a live range with the same
number of instructions as the old range, mark it as RS_Local. When such
a range is seen again, require that it be split in a way that reduces
the number of instructions. That guarantees we are making progress while
still being able to perform 3 -> 2+3 splits as required by PR10070.

This also means that the PrevSlot map is no longer needed. This was also
used to estimate new spill weights, but that is no longer necessary
after slotIndexes::insertMachineInstrInMaps() got the extra Late
insertion argument.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132697 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-06 23:55:20 +00:00
Jakob Stoklund Olesen
5f2316a3b5 Switch AllocationOrder to using RegisterClassInfo instead of a BitVector
of reserved registers.

Use RegisterClassInfo in RABasic as well. This slightly changes som
allocation orders because RegisterClassInfo puts CSR aliases last.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132581 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-03 20:34:53 +00:00
Jakob Stoklund Olesen
76395c9a31 Revert r132358 "Simplify the eviction policy by making the failsafe explicit."
This commit caused regressions in i386 flops-[568], matrix, salsa20,
256.bzip2, and enc-md5.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132413 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-01 18:45:02 +00:00
Jakob Stoklund Olesen
d2056e51c6 Simplify the eviction policy by making the failsafe explicit.
When assigned ranges are evicted, they are put in the RS_Evicted stage and are
not allowed to evict anything else. That prevents looping automatically.

When evicting ranges just to get a cheaper register, use only spill weights to
find the possible candidates. Avoid breaking hints for this purpose, it is not
worth it.

Start implementing more complex eviction heuristics, guarded by the temporary
-complex-eviction flag. The initial version permits a heavier range to be
evicted if it doesn't have any uses where the evicting range is live. This makes
it a good candidate for live ranfge splitting.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132358 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-31 21:02:44 +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