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* Added the MachineSchedulerPass skeleton.Andrew Trick2012-01-13
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148105 91177308-0d34-0410-b5e6-96231b3b80d8
* Make SplitAnalysis::UseSlots private.Jakob Stoklund Olesen2012-01-12
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148031 91177308-0d34-0410-b5e6-96231b3b80d8
* Make data structures private.Jakob Stoklund Olesen2012-01-11
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@147979 91177308-0d34-0410-b5e6-96231b3b80d8
* Stop tracking spill slot uses in VirtRegMap.Jakob Stoklund Olesen2011-11-13
| | | | | | | Nobody cared, StackSlotColoring scans the instructions to find used stack slots. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144485 91177308-0d34-0410-b5e6-96231b3b80d8
* Update split candidate correctly when interference cache is full.Jakob Stoklund Olesen2011-11-01
| | | | | | No test case, spotted by inspection. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@143407 91177308-0d34-0410-b5e6-96231b3b80d8
* Ignore the cloning of unknown registers.Jakob Stoklund Olesen2011-09-14
| | | | | | | | THe LRE_DidCloneVirtReg callback may be called with vitual registers that RAGreedy doesn't even know about yet. In that case, there are no data structures to update. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139702 91177308-0d34-0410-b5e6-96231b3b80d8
* Remove the -compact-regions flag.Jakob Stoklund Olesen2011-09-12
| | | | | | | It has been enabled by default for a while, it was only there to allow performance comparisons. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139501 91177308-0d34-0410-b5e6-96231b3b80d8
* Add an interface for SplitKit complement spill modes.Jakob Stoklund Olesen2011-09-12
| | | | | | | | | | | | | | | | | | | | | | | | | 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
* Make a bunch of symbols private.Benjamin Kramer2011-08-19
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@138025 91177308-0d34-0410-b5e6-96231b3b80d8
* Refer to the RegisterCoalescer pass by ID.Jakob Stoklund Olesen2011-08-09
| | | | | | | 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
* Fix typo. Thanks, Andy!Jakob Stoklund Olesen2011-08-06
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137023 91177308-0d34-0410-b5e6-96231b3b80d8
* Reject RS_Spill ranges from local splitting as well.Jakob Stoklund Olesen2011-08-05
| | | | | | | 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
* Only mark remainder intervals as RS_Spill after per-block splitting.Jakob Stoklund Olesen2011-08-05
| | | | | | | | | | 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
* Remember to update LiveDebugVariables after per-block splitting.Jakob Stoklund Olesen2011-08-05
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136996 91177308-0d34-0410-b5e6-96231b3b80d8
* Extract per-block splitting into its own method.Jakob Stoklund Olesen2011-08-05
| | | | | | No functional change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136994 91177308-0d34-0410-b5e6-96231b3b80d8
* Also use shouldSplitSingleBlock() in the fallback splitting mode.Jakob Stoklund Olesen2011-08-05
| | | | | | | 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
* Split around single instructions to enable register class inflation.Jakob Stoklund Olesen2011-08-05
| | | | | | | | | | | | | 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
* Enable compact region splitting by default.Jakob Stoklund Olesen2011-08-03
| | | | | | | | | | | 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
* Be more conservative when forming compact regions.Jakob Stoklund Olesen2011-08-03
| | | | | | | | | | | | | | | 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
* Fix some warnings from Clang in release builds:Chandler Carruth2011-08-03
| | | | | | | | | | | 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
* Use the precomputed def presence in RAGreedy::calcSpillCost.Jakob Stoklund Olesen2011-08-02
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136742 91177308-0d34-0410-b5e6-96231b3b80d8
* Inform SpillPlacement about blocks with defs.Jakob Stoklund Olesen2011-08-02
| | | | | | 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
* Rename {First,Last}Use to {First,Last}Instr.Jakob Stoklund Olesen2011-08-02
| | | | | | | 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
* Time the emission of debug values.Jakob Stoklund Olesen2011-07-31
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136584 91177308-0d34-0410-b5e6-96231b3b80d8
* Revert r136528 "Enable compact region splitting by default."Jakob Stoklund Olesen2011-07-30
| | | | | | | 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
* Enable compact region splitting by default.Jakob Stoklund Olesen2011-07-29
| | | | | | | 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
* Reverse order of RS_Split live ranges under -compact-regions.Jakob Stoklund Olesen2011-07-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Add support for multi-way live range splitting.Jakob Stoklund Olesen2011-07-26
| | | | | | | | | | | | | | | | | | | | | 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
* Revert to RA_Assign when a virtreg separates into components.Jakob Stoklund Olesen2011-07-26
| | | | | | | | | | | | | 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
* Add an RS_Split2 stage used for loop prevention.Jakob Stoklund Olesen2011-07-25
| | | | | | | | | | | | | | | | 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
* Rename live range stages to better reflect how they are used.Jakob Stoklund Olesen2011-07-25
| | | | | | | | | | | | 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
* Add RAGreedy::calcCompactRegion.Jakob Stoklund Olesen2011-07-23
| | | | | | | | | | | | | | | | 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
* Prepare RAGreedy::growRegion for compact regions.Jakob Stoklund Olesen2011-07-23
| | | | | | | | | | | | | | | 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
* Migrate LLVM and Clang to use the new makeArrayRef(...) functions where ↵Frits van Bommel2011-07-18
| | | | | | | | | 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
* Remove unused LoopRanges from RegAllocGreedy.Jakub Staszak2011-07-16
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135354 91177308-0d34-0410-b5e6-96231b3b80d8
* Extract parts of RAGreedy::splitAroundRegion as SplitKit methods.Jakob Stoklund Olesen2011-07-15
| | | | | | | | | | | 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
* Reapply r135121 with a fixed copy constructor.Jakob Stoklund Olesen2011-07-14
| | | | | | | | | | | | | | | | | | | | | 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
* Revert r135121 which broke a gcc-4.2 builder.Jakob Stoklund Olesen2011-07-14
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135122 91177308-0d34-0410-b5e6-96231b3b80d8
* Count references to interference cache entries.Jakob Stoklund Olesen2011-07-14
| | | | | | | | | | | | | | | | | 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
* Reapply r135074 and r135080 with a fix.Jakob Stoklund Olesen2011-07-14
| | | | | | | | | | 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
* Revert r135074 and r135080. They broke clamscan.Jakob Stoklund Olesen2011-07-13
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@135096 91177308-0d34-0410-b5e6-96231b3b80d8
* Only keep the global split candidates that work out.Jakob Stoklund Olesen2011-07-13
| | | | | | | | | 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
* Move the InterferenceCache cursor into the GlobalSplitCand struct.Jakob Stoklund Olesen2011-07-13
| | | | | | | 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
* Be more aggressive about following hints.Jakob Stoklund Olesen2011-07-08
| | | | | | | | | | | | | | | | | | | | 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
* Break infinite loop when the Hopfield network oscillates.Jakob Stoklund Olesen2011-07-05
| | | | | | | | | | 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
* Tweak comment and debug output.Jakob Stoklund Olesen2011-07-05
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134412 91177308-0d34-0410-b5e6-96231b3b80d8
* Fix PR10244.Jakob Stoklund Olesen2011-07-04
| | | | | | | | | | | | 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
* Use a new strategy for preventing eviction loops in RAGreedy.Jakob Stoklund Olesen2011-07-02
| | | | | | | | | | | | | | | | | | | 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
* Reapply r134047 now that the world is ready for it.Jakob Stoklund Olesen2011-06-30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Revert r134047 while investigating a llvm-gcc-i386-linux-selfhostJakob Stoklund Olesen2011-06-29
| | | | | | miscompile. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134053 91177308-0d34-0410-b5e6-96231b3b80d8
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