aboutsummaryrefslogtreecommitdiff
path: root/lib/CodeGen/SplitKit.cpp
AgeCommit message (Collapse)Author
2012-11-28Make the LiveRegMatrix analysis available to targets.Jakob Stoklund Olesen
No functional change, just moved header files. Targets can inject custom passes between register allocation and rewriting. This makes it possible to tweak the register allocation before rewriting, using the full global interference checking available from LiveRegMatrix. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168806 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-11Release build: guard dump functions withManman Ren
"#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)" No functional change. Update r163339. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163653 91177308-0d34-0410-b5e6-96231b3b80d8
2012-09-06Release build: guard dump functions with "ifndef NDEBUG"Manman Ren
No functional change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@163339 91177308-0d34-0410-b5e6-96231b3b80d8
2012-08-03Fix a couple of loops that were processing unused value numbers.Jakob Stoklund Olesen
Unused VNInfos should be left alone. Their def SlotIndex doesn't point to anything. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161257 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-27Eliminate the IS_PHI_DEF flag and VNInfo::setIsPHIDef().Jakob Stoklund Olesen
A value number is a PHI def if and only if it begins at a block boundary. This can be derived from the def slot, a separate flag is not necessary. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160893 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-04Pass context pointers to LiveRangeCalc::reset().Jakob Stoklund Olesen
Remove the same pointers from all the other LiveRangeCalc functions, simplifying the interface. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157941 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-02Moved LiveRangeEdit.h so that it can be called from other parts of the ↵Pete Cooper
backend, not just libCodeGen git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153906 91177308-0d34-0410-b5e6-96231b3b80d8
2012-04-02Refactored the LiveRangeEdit interface so that MachineFunction, ↵Pete Cooper
TargetInstrInfo, MachineRegisterInfo, LiveIntervals, and VirtRegMap are all passed into the constructor and stored as members instead of passed in to each method. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153903 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-04Don't store COPY pointers in VNInfo.Jakob Stoklund Olesen
If a value is defined by a COPY, that instuction can easily and cheaply be found by getInstructionFromIndex(VNI->def). This reduces the size of VNInfo from 24 to 16 bytes, and improves llc compile time by 3%. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149763 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-20More dead code removal (using -Wunreachable-code)David Blaikie
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148578 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-11Detect when a value is undefined on an edge to a landing pad.Jakob Stoklund Olesen
Consider this code: int h() { int x; try { x = f(); g(); } catch (...) { return x+1; } return x; } The variable x is undefined on the first edge to the landing pad, but it has the f() return value on the second edge to the landing pad. SplitAnalysis::getLastSplitPoint() would assume that the return value from f() was live into the landing pad when f() throws, which is of course impossible. Detect these cases, and treat them as if the landing pad wasn't there. This allows spill code to be inserted after the function call to f(). <rdar://problem/10664933> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147912 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-11Exclusively use SplitAnalysis::getLastSplitPoint().Jakob Stoklund Olesen
Delete the alternative implementation in LiveIntervalAnalysis. These functions computed the same thing, but SplitAnalysis caches the result. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147911 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-07Add bundle aware API for querying instruction properties and switch the codeEvan Cheng
generator to it. For non-bundle instructions, these behave exactly the same as the MC layer API. For properties like mayLoad / mayStore, look into the bundle and if any of the bundled instructions has the property it would return true. For properties like isPredicable, only return true if *all* of the bundled instructions have the property. For properties like canFoldAsLoad, isCompare, conservatively return false for bundles. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@146026 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-14Use getVNInfoBefore() when it makes sense.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144517 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-13Terminate all dead defs at the dead slot instead of the 'next' slot.Jakob Stoklund Olesen
This makes no difference for normal defs, but early clobber dead defs now look like: [Slot_EarlyClobber; Slot_Dead) instead of: [Slot_EarlyClobber; Slot_Register). Live ranges for normal dead defs look like: [Slot_Register; Slot_Dead) as before. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144512 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-13Rename SlotIndexes to match how they are used.Jakob Stoklund Olesen
The old naming scheme (load/use/def/store) can be traced back to an old linear scan article, but the names don't match how slots are actually used. The load and store slots are not needed after the deferred spill code insertion framework was deleted. The use and def slots don't make any sense because we are using half-open intervals as is customary in C code, but the names suggest closed intervals. In reality, these slots were used to distinguish early-clobber defs from normal defs. The new naming scheme also has 4 slots, but the names match how the slots are really used. This is a purely mechanical renaming, but some of the code makes a lot more sense now. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144503 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-16Spill mode: Hoist back-copies locally.Jakob Stoklund Olesen
The leaveIntvAfter() function normally inserts a back-copy after the requested instruction, making the back-copy kill the live range. In spill mode, try to insert the back-copy before the last use instead. That means the last use becomes the kill instead of the back-copy. This lowers the register pressure because the last use can now redefine the same register it was reading. This will also improve compile time: The back-copy isn't a kill, so hoisting it in hoistCopiesForSize() won't force a recomputation of the source live range. Similarly, if the back-copy isn't hoisted by the splitter, the spiller will not attempt hoisting it locally. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139883 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-14Hoist back-copies to the least busy dominator.Jakob Stoklund Olesen
When a back-copy is hoisted to the nearest common dominator, keep looking up the dominator tree for a less loopy dominator, and place the back-copy there instead. Don't do this when a single existing back-copy dominates all the others. Assume the client knows what he is doing, and keep the dominating back-copy. This prevents us from hoisting back-copies into loops in most cases. If a value is defined in a loop with multiple exits, we may still hoist back-copies into that loop. That is the speed/size tradeoff. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139698 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-13Distinguish complex mapped values from forced recomputation.Jakob Stoklund Olesen
When a ParentVNI maps to multiple defs in a new interval, its live range may still be derived directly from RegAssign by transferValues(). On the other hand, when instructions have been rematerialized or hoisted, it may be necessary to completely recompute live ranges using LiveRangeCalc::extend() to all uses. Use a bit in the value map to indicate that a live range must be recomputed. Rename markComplexMapped() to forceRecompute(). This fixes some live range verification errors when -split-spill-mode=size hoists back-copies by recomputing source ranges when RegAssign kills can't be moved. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139660 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-13Implement -split-spill-mode=size.Jakob Stoklund Olesen
Whenever the complement interval is defined by multiple copies of the same value, hoist those back-copies to the nearest common dominator. This ensures that at most one copy is inserted per value in the complement inteval, and no phi-defs are needed. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139651 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-13Add SplitEditor::markOverlappedComplement().Jakob Stoklund Olesen
This function is used to flag values where the complement interval may overlap other intervals. Call it from overlapIntv, and use the flag to fully recompute those live ranges in transferValues(). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139612 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-13Eliminate the extendRange() wrapper.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139608 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-13Switch extendInBlock() to take a kill slot instead of the last use slot.Jakob Stoklund Olesen
Three out of four clients prefer this interface which is consistent with extendIntervalEndTo() and LiveRangeCalc::extend(). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139604 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-13Use a separate LiveRangeCalc for the complement in spill modes.Jakob Stoklund Olesen
The complement interval may overlap the other intervals created, so use a separate LiveRangeCalc instance to compute its live range. A LiveRangeCalc instance can only be shared among non-overlapping intervals. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139603 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-13Extract live range calculations from SplitKit.Jakob Stoklund Olesen
SplitKit will soon need two copies of these data structures, and the algorithms will also be useful when LiveIntervalAnalysis becomes independent of LiveVariables. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139572 91177308-0d34-0410-b5e6-96231b3b80d8
2011-09-12Add an interface for SplitKit complement spill modes.Jakob Stoklund Olesen
SplitKit always computes a complement live range to cover the places where the original live range was live, but no explicit region has been allocated. Currently, the complement live range is created to be as small as possible - it never overlaps any of the regions. This minimizes register pressure, but if the complement is going to be spilled anyway, that is not very important. The spiller will eliminate redundant spills, and hoist others by making the spill slot live range overlap some of the regions created by splitting. Stack slots are cheap. This patch adds the interface to enable spill modes in SplitKit. In spill mode, SplitKit will assume that the complement is going to spill, so it will allow it to overlap regions in order to avoid back-copies. By doing some of the spiller's work early, the complement live range becomes simpler. In some cases, it can become much simpler because no extra PHI-defs are required. This will speed up both splitting and spilling. This is only the interface to enable spill modes, no implementation yet. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139500 91177308-0d34-0410-b5e6-96231b3b80d8
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