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path: root/lib/CodeGen/PHIElimination.cpp
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2012-07-20Split loop exiting edges more aggressively.Jakob Stoklund Olesen1-13/+56
PHIElimination splits critical edges when it predicts it can resolve interference and eliminate copies. It doesn't split the edge if the interference wouldn't be resolved anyway because the phi-use register is live in the critical edge anyway. Teach PHIElimination to split loop exiting edges with interference, even if it wouldn't resolve the interference. This removes the necessary copies from the loop, which is still an improvement from injecting the copies into the loop. The test case demonstrates the improvement. Before: LBB0_1: cmpb $0, (%rdx) leaq 1(%rdx), %rdx movl %esi, %eax je LBB0_1 After: LBB0_1: cmpb $0, (%rdx) leaq 1(%rdx), %rdx je LBB0_1 movl %esi, %eax git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160571 91177308-0d34-0410-b5e6-96231b3b80d8
2012-07-04Allow multiple terminators to read virtual registers.Jakob Stoklund Olesen1-33/+29
Find the kill as the last terminator to read SrcReg. Patch by Philipp Brüschweiler! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159722 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-25Teach PHIElimination to handle <undef> operands.Jakob Stoklund Olesen1-19/+34
When a PHI use is <undef>, don't emit a copy in the predecessor block, but insert an IMPLICIT_DEF instruction instead. This ensures that virtual register uses are always jointly dominated by defs, even if some of them are IMPLICIT_DEF. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159121 91177308-0d34-0410-b5e6-96231b3b80d8
2012-02-10RegAlloc superpass: includes phi elimination, coalescing, and scheduling.Andrew Trick1-3/+7
Creates a configurable regalloc pipeline. Ensure specific llc options do what they say and nothing more: -reglloc=... has no effect other than selecting the allocator pass itself. This patch introduces a new umbrella flag, "-optimize-regalloc", to enable/disable the optimizing regalloc "superpass". This allows for example testing coalscing and scheduling under -O0 or vice-versa. When a CodeGen pass requires the MachineFunction to have a particular property, we need to explicitly define that property so it can be directly queried rather than naming a specific Pass. For example, to check for SSA, use MRI->isSSA, not addRequired<PHIElimination>. CodeGen transformation passes are never "required" as an analysis ProcessImplicitDefs does not require LiveVariables. We have a plan to massively simplify some of the early passes within the regalloc superpass. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@150226 91177308-0d34-0410-b5e6-96231b3b80d8
2012-01-20Delete an unused member variable.Jakob Stoklund Olesen1-1/+0
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@148594 91177308-0d34-0410-b5e6-96231b3b80d8
2011-12-06First chunk of MachineInstr bundle support.Evan Cheng1-1/+1
1. Added opcode BUNDLE 2. Taught MachineInstr class to deal with bundled MIs 3. Changed MachineBasicBlock iterator to skip over bundled MIs; added an iterator to walk all the MIs 4. Taught MachineBasicBlock methods about bundled MIs git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145975 91177308-0d34-0410-b5e6-96231b3b80d8
2011-07-29Add an isSSA() flag to MachineRegisterInfo.Jakob Stoklund Olesen1-0/+3
This flag is true from isel to register allocation when the machine function is required to be in SSA form. The TwoAddressInstructionPass and PHIElimination passes clear the flag. The SSA flag wil be used by the machine code verifier to check for SSA form, and eventually an assertion can enforce it in +Asserts builds. This will catch the common target error of creating machine code with multiple defs of a virtual register. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136532 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-23Remove unused STL header includes.Jay Foad1-1/+0
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130068 91177308-0d34-0410-b5e6-96231b3b80d8
2011-03-10Add an option to disable critical edge splitting in PHIElimination.Cameron Zwarich1-4/+12
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127398 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17Adjust indenting of arguments.Cameron Zwarich1-3/+3
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125727 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-17Return Changed from SplitPHIEdges rather than always returning true.Cameron Zwarich1-1/+1
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125726 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-14Add a statistic to PHIElimination tracking the number of critical edges split.Cameron Zwarich1-2/+7
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125476 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-14Try for the third time to teach getFirstTerminator() about debug values.Jakob Stoklund Olesen1-2/+8
This time let's rephrase to trick gcc-4.3 into not miscompiling. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123432 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-14Revert r123419. It still breaks llvm-gcc-i386-linux-selfhost.Jakob Stoklund Olesen1-8/+2
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123423 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-14Try again to teach getFirstTerminator() about debug values.Jakob Stoklund Olesen1-2/+8
Fix some callers to better deal with debug values. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123419 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-13Speculatively revert r123384 to make llvm-gcc-i386-linux-selfhost buildbot ↵Devang Patel1-2/+0
happy. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123389 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-13Teach MachineBasicBlock::getFirstTerminator to ignore debug values.Jakob Stoklund Olesen1-0/+2
It will still return an iterator that points to the first terminator or end(), but there may be DBG_VALUE instructions following the first terminator. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123384 91177308-0d34-0410-b5e6-96231b3b80d8
2011-01-09Replace TargetRegisterInfo::printReg with a PrintReg class that also works ↵Jakob Stoklund Olesen1-1/+1
without a TRI instance. Print virtual registers numbered from 0 instead of the arbitrary FirstVirtualRegister. The first virtual register is printed as %vreg0. TRI::NoRegister is printed as %noreg. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123107 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-05Remove the PHIElimination.h header, as it is no longer needed.Cameron Zwarich1-8/+55
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120959 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-05Move the FindCopyInsertPoint method of PHIElimination to a new standaloneCameron Zwarich1-45/+2
function so that it can be shared with StrongPHIElimination. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120951 91177308-0d34-0410-b5e6-96231b3b80d8
2010-12-04Remove PHIElimination's private copy of SkipPHIsAndLabels.Cameron Zwarich1-2/+2
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120918 91177308-0d34-0410-b5e6-96231b3b80d8
2010-10-07Now with fewer extraneous semicolons!Owen Anderson1-1/+1
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115996 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-23Now that PassInfo and Pass::ID have been separated, move the rest of the ↵Owen Anderson1-2/+2
passes over to the new registration API. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111815 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-18Preserve subregs on PHI source operands. Patch by Krister Wombell!Jakob Stoklund Olesen1-1/+4
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111366 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-17PHI elimination shouldn't require machineloopinfo since it's used at -O0. ↵Evan Cheng1-7/+9
Move the requirement to LiveIntervalAnalysis instead. Note this does not change the number of times machineloopinfo is computed. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111285 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-17Move the decision logic whether it's a good idea to split a critical edge to ↵Evan Cheng1-2/+9
clients. Also fixed an erroneous check. An edge is only a back edge when the from and to blocks are in the same loop. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111256 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-17PHI elimination should not break back edge. It can cause some significant ↵Evan Cheng1-3/+5
code placement issues. rdar://8263994 good: LBB0_2: mov r2, r0 . . . mov r1, r2 bne LBB0_2 bad: LBB0_2: mov r2, r0 . . . @ BB#3: mov r1, r2 b LBB0_2 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111221 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-06Reapply r110396, with fixes to appease the Linux buildbot gods.Owen Anderson1-1/+1
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110460 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-06Revert r110396 to fix buildbots.Owen Anderson1-1/+1
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110410 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-05Don't use PassInfo* as a type identifier for passes. Instead, use the ↵Owen Anderson1-1/+1
address of the static ID member as the sole unique type identifier. Clean up APIs related to this change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110396 91177308-0d34-0410-b5e6-96231b3b80d8
2010-07-10Emit COPY instructions instead of using copyRegToReg in InstrEmitter,Jakob Stoklund Olesen1-5/+6
ScheduleDAGEmit, TwoAddressLowering, and PHIElimination. This switches the bulk of register copies to using COPY, but many less used copyRegToReg calls remain. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108050 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-22Move PHIElimination's SplitCriticalEdge for MachineBasicBlocks outDan Gohman1-52/+1
into a utility routine, teach it how to update MachineLoopInfo, and make use of it in MachineLICM to split critical edges on demand. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106555 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-17Add a DebugLoc parameter to TargetInstrInfo::InsertBranch(). ThisStuart Hastings1-1/+2
addresses a longstanding deficiency noted in many FIXMEs scattered across all the targets. This effectively moves the problem up one level, replacing eleven FIXMEs in the targets with eight FIXMEs in CodeGen, plus one path through FastISel where we actually supply a DebugLoc, fixing Radar 7421831. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106243 91177308-0d34-0410-b5e6-96231b3b80d8
2010-05-06Add a DebugLoc argument to TargetInstrInfo::copyRegToReg, so that itDan Gohman1-2/+4
doesn't have to guess. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103194 91177308-0d34-0410-b5e6-96231b3b80d8
2010-05-05Move REG_SEQUENCE removal to 2addr pass.Evan Cheng1-61/+0
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103109 91177308-0d34-0410-b5e6-96231b3b80d8
2010-05-04Teach PHI elimination to remove REG_SEQUENCE instructions and update ↵Evan Cheng1-0/+60
references of the source operands with references of the destination with subreg indices. e.g. %reg1029<def>, %reg1030<def> = VLD1q16 %reg1024<kill>, ... %reg1031<def> = REG_SEQUENCE %reg1029<kill>, 5, %reg1030<kill>, 6 => %reg1031:5<def>, %reg1031:6<def> = VLD1q16 %reg1024<kill>, ... PHI elimination now does more than phi elimination. It is really a de-SSA pass. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103039 91177308-0d34-0410-b5e6-96231b3b80d8
2010-05-04Rename variables for consistency.Evan Cheng1-10/+11
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103013 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-25Avoid being influenced by dbg_value instructions.Evan Cheng1-1/+1
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99465 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-03Remove PHINodeTraits and use MachineInstrExpressionTrait instead.Evan Cheng1-31/+0
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97687 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-23Keep track of phi join registers explicitly in LiveVariables.Jakob Stoklund Olesen1-0/+1
Previously, LiveIntervalAnalysis would infer phi joins by looking for multiply defined registers. That doesn't work if the phi join is implicitly defined in all but one of the predecessors. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96994 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-23Dead code eliminationJakob Stoklund Olesen1-5/+0
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96837 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-17Dead code elimination.Jakob Stoklund Olesen1-4/+0
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96496 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-09move target-independent opcodes out of TargetInstrInfoChris Lattner1-10/+10
into TargetOpcodes.h. #include the new TargetOpcodes.h into MachineInstr. Add new inline accessors (like isPHI()) to MachineInstr, and start using them throughout the codebase. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95687 91177308-0d34-0410-b5e6-96231b3b80d8
2010-01-05Change errs() to dbgs().David Greene1-3/+3
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92566 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-17Turn off critical edge splitting for landing pads. The introduction of aBill Wendling1-3/+4
non-landing pad basic block as the successor to a block that ends in an unconditional jump will cause block folding to remove the added block as a successor. Thus eventually removing it AND the landing pad entirely. Critical edge splitting is an optimization, so we can safely turn it off when dealing with landing pads. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91634 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-16Reuse lowered phi nodes.Jakob Stoklund Olesen1-13/+86
Tail duplication produces lots of identical phi nodes in different basic blocks. Teach PHIElimination to reuse the join registers when lowering a phi node that is identical to an already lowered node. This saves virtual registers, and more importantly it avoids creating copies the the coalescer doesn't know how to eliminate. Teach LiveIntervalAnalysis about the phi joins with multiple uses. This patch significantly reduces code size produced by -pre-regalloc-taildup. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91549 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-03improve portability to avoid conflicting with std::next in c++'0x.Chris Lattner1-3/+3
Patch by Howard Hinnant! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90365 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-01Move PHIElimination::isLiveOut method to LiveVariables.Jakob Stoklund Olesen1-48/+2
We want LiveVariables clients to use methods rather than accessing the getVarInfo data structure directly. That way it will be possible to change the LiveVariables representation. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90240 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-21Be more clever about calculating live variables through new basic blocks.Jakob Stoklund Olesen1-18/+2
When splitting a critical edge, the registers live through the edge are: - Used in a PHI instruction, or - Live out from the predecessor, and - Live in to the successor. This allows the coalescer to eliminate even more phi joins. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89530 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-19Place new basic blocks immediately after their predecessor when splittingJakob Stoklund Olesen1-7/+7
critical edges in PHIElimination. This has a huge impact on regalloc performance, and we recover almost all of the 10% compile time regression that edge splitting introduced. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89381 91177308-0d34-0410-b5e6-96231b3b80d8
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