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path: root/lib/CodeGen/SplitKit.cpp
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2011-08-05Delete getMultiUseBlocks and splitSingleBlocks.Jakob Stoklund Olesen
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
2011-08-05Split around single instructions to enable register class inflation.Jakob Stoklund Olesen
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
2011-08-02Rename {First,Last}Use to {First,Last}Instr.Jakob Stoklund Olesen
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
2011-08-02Add a BlockInfo::FirstDef field.Jakob Stoklund Olesen
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
2011-08-02Delete BlockInfo::LiveThrough. It wasn't used any more.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136735 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-24Never extend live ranges for <undef> uses.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135886 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-24Correctly handle <undef> tied uses when rewriting after a split.Jakob Stoklund Olesen
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
2011-07-23Fix bug in SplitEditor::splitLiveThroughBlock when switching registers.Jakob Stoklund Olesen
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
2011-07-18Fix a crash when building 177.mesa for armv6.Jakob Stoklund Olesen
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
2011-07-16Silence unused variable warningMatt Beaumont-Gay
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135339 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-16He said *before* the last split point.Jakob Stoklund Olesen
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
2011-07-15Extract parts of RAGreedy::splitAroundRegion as SplitKit methods.Jakob Stoklund Olesen
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
2011-06-30Reapply r134047 now that the world is ready for it.Jakob Stoklund Olesen
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
2011-06-29Revert r134047 while investigating a llvm-gcc-i386-linux-selfhostJakob Stoklund Olesen
miscompile. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134053 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-29Rewrite RAGreedy::splitAroundRegion, now with cool ASCII art.Jakob Stoklund Olesen
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
2011-06-28Fix a bad iterator dereference that Evan uncovered.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133978 91177308-0d34-0410-b5e6-96231b3b80d8
2011-06-26There is only one register coalescer. Merge it into the base class andRafael Espindola
remove the analysis group. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@133899 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-30Reapply r132245 with a fix for the bug that broke the darwin9/i386 build.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132309 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-29Revert r132245, "Create two BlockInfo entries when a live range is ↵Jakob Stoklund Olesen
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
2011-05-28Create two BlockInfo entries when a live range is discontinuous through a block.Jakob Stoklund Olesen
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
2011-05-28Add SplitAnalysis::getNumLiveBlocks().Jakob Stoklund Olesen
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
2011-05-10Fix PR9883. Make sure all caches are invalidated when a live range is repaired.Jakob Stoklund Olesen
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
2011-05-05Add some statistics to the splitting and spilling frameworks.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130931 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-03Gracefully handle invalid live ranges. Fix PR9831.Jakob Stoklund Olesen
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
2011-05-02Minimize the slot indexes spanned by register ranges created when splitting.Jakob Stoklund Olesen
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
2011-04-26Add a safe-guard against repeated splitting for some rare cases.Jakob Stoklund Olesen
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
2011-04-21Don't recycle loop variables.Matt Beaumont-Gay
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129928 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-21Allow allocatable ranges from global live range splitting to be split again.Jakob Stoklund Olesen
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
2011-04-16Unbreak the MSVC 2010 build.Francois Pichet
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
2011-04-15Teach the SplitKit blitter to handle multiply defined values as well.Jakob Stoklund Olesen
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
2011-04-13Stop using dead function.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129442 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-12Create new intervals for isolated blocks during region splitting.Jakob Stoklund Olesen
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
2011-04-12Add SplitKit API to query and select the current interval being worked on.Jakob Stoklund Olesen
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
2011-04-09Build the Hopfield network incrementally when splitting global live ranges.Jakob Stoklund Olesen
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
2011-04-06Analyze blocks with uses separately from live-through blocks without uses.Jakob Stoklund Olesen
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
2011-04-05Sign errorJakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128963 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-05Don't crash when a value is defined after the last split point.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128962 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-05Use std::unique instead of a SmallPtrSet to ensure unique instructions in ↵Jakob Stoklund Olesen
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
2011-04-05Stop precomputing last split points, query the SplitAnalysis cache on demand.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128875 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-05Cache the fairly expensive last split point computation and provide a fastJakob Stoklund Olesen
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
2011-04-04Stop caching basic block index ranges now that SlotIndexes can keep up.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128821 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-29Recompute register class and hint for registers created during spilling.Jakob Stoklund Olesen
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
2011-03-29Handle the special case when all uses follow the last split point.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128450 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-27Amend debug output.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128398 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-20Process all dead defs after rematerializing during splitting.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127973 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-18Be more accurate about the slot index reading a register when dealing with defsJakob Stoklund Olesen
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
2011-03-17Dead code elimination may separate the live interval into multiple connected ↵Jakob Stoklund Olesen
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
2011-03-17Rewrite instructions as part of ConnectedVNInfoEqClasses::Distribute.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127779 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-15Preserve both isPHIDef and isDefByCopy bits when copying parent values.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127697 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-08Delete dead code after rematerializing.Jakob Stoklund Olesen
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
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