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path: root/lib/CodeGen/SplitKit.h
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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
2011-04-12SparseBitVector is SLOW.Jakob Stoklund Olesen
Use a Bitvector instead, we didn't need the smaller memory footprint anyway. This makes the greedy register allocator 10% faster. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129390 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
2011-04-05Use 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
2011-04-04Delete leftover data members.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@128820 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
2011-03-08Delete 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
2011-03-05Work around a coalescer bug.Jakob Stoklund Olesen
The coalescer can in very rare cases leave too large live intervals around after rematerializing cheap-as-a-move instructions. Linear scan doesn't really care, but live range splitting gets very confused when a live range is killed by a ghost instruction. I will fix this properly in the coalescer after 2.9 branches. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127096 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-04Use an IndexedMap instead of a DenseMap for the live-out cache.Jakob Stoklund Olesen
This speeds up updateSSA() so it only accounts for 5% of the live range splitting time. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126972 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-03Cache basic block bounds instead of asking SlotIndexes::getMBBRange all the ↵Jakob Stoklund Olesen
time. This speeds up the greedy register allocator by 15%. DenseMap is not as fast as one might hope. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126921 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-03Change the SplitEditor interface to a single instance can be shared for ↵Jakob Stoklund Olesen
multiple splits. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126912 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-02Turn the Edit member into a pointer so it can change dynamically.Jakob Stoklund Olesen
No functional change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126898 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-02Transfer simply defined values directly without recomputing liveness and SSA.Jakob Stoklund Olesen
Values that map to a single new value in a new interval after splitting don't need new PHIDefs, and if the parent value was never rematerialized the live range will be the same. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126894 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-02Extract a method. No functional change.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126893 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-02Move extendRange() into SplitEditor and delete the LiveRangeMap class.Jakob Stoklund Olesen
Extract the updateSSA() method from the too long extendRange(). LiveOutCache can be shared among all the new intervals since there is at most one of the new ranges live out from each basic block. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126818 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-02Rename mapValue to extendRange because that is its function now.Jakob Stoklund Olesen
Simplify the signature - The return value and ParentVNI are no longer needed. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126809 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-02Move LiveIntervalMap::extendTo into LiveInterval itself.Jakob Stoklund Olesen
This method could probably be used by LiveIntervalAnalysis::shrinkToUses, and now it can use extendIntervalEndTo() which coalesces ranges. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126803 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-01Delete dead code.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126801 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-01Move the value map from LiveIntervalMap to SplitEditor.Jakob Stoklund Olesen
The value map is currently not used, all values are 'complex mapped' and LiveIntervalMap::mapValue is used to dig them out. This is the first step in a series changes leading to the removal of LiveIntervalMap. Its data structures can be shared among all the live intervals created by a split, so it is wasteful to create a copy for each. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126800 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-01Delete dead code.Jakob Stoklund Olesen
Local live range splitting is better driven by interference. This code was just guessing. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126799 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-21Add SplitKit::isOriginalEndpoint and use it to force live range splitting to ↵Jakob Stoklund Olesen
terminate. An original endpoint is an instruction that killed or defined the original live range before any live ranges were split. When splitting global live ranges, avoid creating local live ranges without any original endpoints. We may still create global live ranges without original endpoints, but such a range won't be split again, and live range splitting still terminates. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126151 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-19Give SplitAnalysis a VRM member to access VirtRegMap::getOriginal().Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126005 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-19Missed member rename for naming convention.Jakob Stoklund Olesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126003 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17Split local live ranges.Jakob Stoklund Olesen
A local live range is live in a single basic block. If such a range fails to allocate, try to find a sub-range that would get a larger spill weight than its interference. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125764 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-09Delete unused code for analyzing and splitting around loops.Jakob Stoklund Olesen
Loop splitting is better handled by the more generic global region splitting based on the edge bundle graph. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125243 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-09Use the LiveBLocks array for SplitEditor::splitSingleBlocks() as well.Jakob Stoklund Olesen
This fixes a bug where splitSingleBlocks() could split a live range after a terminator instruction. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125237 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-09Move calcLiveBlockInfo() and the BlockInfo struct into SplitAnalysis.Jakob Stoklund Olesen
No functional changes intended. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125231 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-08Add SplitEditor::overlapIntv() to create small ranges where both registers ↵Jakob Stoklund Olesen
are live. If a live range is used by a terminator instruction, and that live range needs to leave the block on the stack or in a different register, it can be necessary to have both sides of the split live at the terminator instruction. Example: %vreg2 = COPY %vreg1 JMP %vreg1 Becomes after spilling %vreg2: SPILL %vreg1 JMP %vreg1 The spill doesn't kill the register as is normally the case. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125102 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-03Return live range end points from SplitEditor::enter*/leave*.Jakob Stoklund Olesen
These end points come from the inserted copies, and can be passed directly to useIntv. This simplifies the coloring code. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124799 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-03Reapply this.Eric Christopher
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124779 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-03Temporarily revert 124765 in an attempt to find the cycle breaking bootstrap.Eric Christopher
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124778 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-03Defer SplitKit value mapping until all defs are available.Jakob Stoklund Olesen
The greedy register allocator revealed some problems with the value mapping in SplitKit. We would sometimes start mapping values before all defs were known, and that could change a value from a simple 1-1 mapping to a multi-def mapping that requires ssa update. The new approach collects all defs and register assignments first without filling in any live intervals. Only when finish() is called, do we compute liveness and mapped values. At this time we know with certainty which values map to multiple values in a split range. This also has the advantage that we can compute live ranges based on the remaining uses after rematerializing at split points. The current implementation has many opportunities for compile time optimization. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124765 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-26Rename member variables to follow the rest of LLVM.Jakob Stoklund Olesen
No functional change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124257 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-20Add LiveIntervalMap::dumpCache() to print out the cache used by the ssa ↵Jakob Stoklund Olesen
update algorithm. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123925 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-18Add RAGreedy methods for splitting live ranges around regions.Jakob Stoklund Olesen
Analyze the live range's behavior entering and leaving basic blocks. Compute an interference pattern for each allocation candidate, and use SpillPlacement to find an optimal region where that register can be live. This code is still not enabled. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123774 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-04Turn the EdgeBundles class into a stand-alone machine CFG analysis pass.Jakob Stoklund Olesen
The analysis will be needed by both the greedy register allocator and the X86FloatingPoint pass. It only needs to be computed once when the CFG doesn't change. This pass is very fast, usually showing up as 0.0% wall time. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122832 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-21Add EdgeBundles to SplitKit.Jakob Stoklund Olesen
Edge bundles is an annotation on the CFG that turns it into a bipartite directed graph where each basic block is connected to an outgoing and an ingoing bundle. These bundles are useful for identifying regions of the CFG for live range splitting. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122301 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15Detect and enumerate bypass loops.Jakob Stoklund Olesen
Bypass loops have the current live range live through, but contain no uses or defs. Splitting around a bypass loop can free registers for other uses inside the loop by spilling the split range. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121871 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-15Separate SplitAnalysis::getSplitLoops().Jakob Stoklund Olesen
This method returns the set of loops with uses that are candidates for splitting. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121870 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-10Basic rematerialization during splitting.Jakob Stoklund Olesen
Whenever splitting wants to insert a copy, it checks if the value can be rematerialized cheaply instead. Missing features: - Delete instructions when all uses have been rematerialized. - Truncate live ranges to the remaining uses after rematerialization. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118702 91177308-0d34-0410-b5e6-96231b3b80d8
2010-11-01When inserting copies during splitting, always use the parent register as theJakob Stoklund Olesen
source, and let rewrite() clean it up. This way, kill flags on the inserted copies are fixed as well during rewrite(). We can't just assume that all the copies we insert are going to be kills since critical edges into loop headers sometimes require both source and dest to be live out of a block. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117980 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-28Replace SplitKit SSA update with an iterative algorithm very similar to the oneJakob Stoklund Olesen
in SSAUpdaterImpl.h Verifying live intervals revealed that the old method was completely wrong, and we need an iterative approach to calculating PHI placemant. Fortunately, we have MachineDominators available, so we don't have to compute that over and over like SSAUpdaterImpl.h must. Live-out values are cached between calls to mapValue() and computed in a greedy way, so most calls will be working with very small block sets. Thanks to Bob for explaining how this should work. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117599 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-28Make MachineDominators available for SplitEditor. We are going to need it forJakob Stoklund Olesen
proper SSA updating. This doesn't cause MachineDominators to be recomputed since we are already requiring MachineLoopInfo which uses dominators as well. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117598 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-27Handle critical loop predecessors by making both inside and outside registersJakob Stoklund Olesen
live out. This doesn't prevent us from inserting a loop preheader later on, if that is better. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@117424 91177308-0d34-0410-b5e6-96231b3b80d8
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