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path: root/lib/CodeGen/BranchFolding.cpp
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2009-11-11Revert this line of 86871.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86875 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-11Add support for tail duplication to BranchFolding, and extendDan Gohman
tail merging support to handle more cases. - Recognize several cases where tail merging is beneficial even when the tail size is smaller than the generic threshold. - Make use of MachineInstrDesc::isBarrier to help detect non-fallthrough blocks. - Check for and avoid disrupting fall-through edges in more cases. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86871 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-11Fix indentation level.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86856 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-11Whitespace cleanups.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86855 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-11Prefix MBB numbers with "BB#" in debug output to make it clear whatDan Gohman
the numbers mean. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86854 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-11Minor code simplification.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86853 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-10Remove an unused variable.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86642 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-10Minor code simplification.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86641 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-03Fix branch folding bug for indirect branches: for a block containing onlyBob Wilson
an unconditional branch (possibly from tail merging), this code is trying to redirect all of its predecessors to go directly to the branch target, but that isn't feasible for indirect branches. The other predecessors (that don't end with indirect branches) could theoretically still be handled, but that is not easily done right now. The AnalyzeBranch interface doesn't currently let us distinguish jump table branches from indirect branches, and this code is currently handling jump tables. To avoid punting on address-taken blocks, we would have to give up handling jump tables. That seems like a bad tradeoff. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85975 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-30Don't delete blocks which have their address taken.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85572 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-29Refactor complicated predicate into a separate function.Bob Wilson
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85519 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-28Reimplement BranchFolding change to avoid tail merging for a 1 instructionBob Wilson
common tail, except when the OptimizeForSize function attribute is present. Radar 7338114. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85441 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-28Revert r85346 change to control tail merging by CodeGenOpt::Level.Bob Wilson
I'm going to redo this using the OptimizeForSize function attribute. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85426 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-27Record CodeGen optimization level in the BranchFolding pass so that we canBob Wilson
use it to control tail merging when there is a tradeoff between performance and code size. When there is only 1 instruction in the common tail, we have been merging. That can be good for code size but is a definite loss for performance. Now we will avoid tail merging in that case when the optimization level is "Aggressive", i.e., "-O3". Radar 7338114. Since the IfConversion pass invokes BranchFolding, it too needs to know the optimization level. Note that I removed the RegisterPass instantiation for IfConversion because it required a default constructor. If someone wants to keep that for some reason, we can add a default constructor with a hard-wired optimization level. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85346 91177308-0d34-0410-b5e6-96231b3b80d8
2009-10-22Revert the main portion of r31856. It was causing BranchFoldingDan Gohman
to break up CFG diamonds by banishing one of the blocks to the end of the function, which is bad for code density and branch size. This does pessimize MultiSource/Benchmarks/Ptrdist/yacr2, the benchmark cited as the reason for the change, however I've examined the code and it looks more like a case of gaming a particular branch than of being generally applicable. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84803 91177308-0d34-0410-b5e6-96231b3b80d8
2009-09-04Run branch folding if if-converter make some transformations.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80994 91177308-0d34-0410-b5e6-96231b3b80d8
2009-09-03Funky indentation.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80971 91177308-0d34-0410-b5e6-96231b3b80d8
2009-08-22Convert DOUT to DEBUG(errs()...).Bill Wendling
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79747 91177308-0d34-0410-b5e6-96231b3b80d8
2009-08-18Make tail merging handle blocks with repeated predecessors correctly, andDan Gohman
remove RemoveDuplicateSuccessor, as it is no longer necessary, and because it breaks assumptions made in MachineBasicBlock::isOnlyReachableByFallthrough. Convert test/CodeGen/X86/omit-label.ll to FileCheck and add a testcase for PR4732. test/CodeGen/Thumb2/thumb2-ifcvt2.ll sees a diff with this commit due to it being bugpoint-reduced to the point where it doesn't matter what the condition for the branch is. Add some more interesting code to test/CodeGen/X86/2009-08-06-branchfolder-crash.ll, which is the testcase that originally motivated the RemoveDuplicateSuccessor code, to help verify that the original problem isn't being re-broken. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@79338 91177308-0d34-0410-b5e6-96231b3b80d8
2009-08-07Rewrite previous patch to follow Chris' stylisticDale Johannesen
preference; no functional change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78391 91177308-0d34-0410-b5e6-96231b3b80d8
2009-08-06Fix PR 4626, a crash in branch folding after OptimizeBlockDale Johannesen
produced a CFG it wasn't prepared for. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78351 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-14llvm_unreachable->llvm_unreachable(0), LLVM_UNREACHABLE->llvm_unreachable.Torok Edwin
This adds location info for all llvm_unreachable calls (which is a macro now) in !NDEBUG builds. In NDEBUG builds location info and the message is off (it only prints "UREACHABLE executed"). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75640 91177308-0d34-0410-b5e6-96231b3b80d8
2009-07-11assert(0) -> LLVM_UNREACHABLE.Torok Edwin
Make llvm_unreachable take an optional string, thus moving the cerr<< out of line. LLVM_UNREACHABLE is now a simple wrapper that makes the message go away for NDEBUG builds. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75379 91177308-0d34-0410-b5e6-96231b3b80d8
2009-05-11Fix PR4188. TailMerging can't tolerate inexactDale Johannesen
sucessor info. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@71478 91177308-0d34-0410-b5e6-96231b3b80d8
2009-02-09Turns out AnalyzeBranch can modify the mbb being analyzed. This is a nastyEvan Cheng
suprise to some callers, e.g. register coalescer. For now, add an parameter that tells AnalyzeBranch whether it's safe to modify the mbb. A better solution is out there, but I don't have time to deal with it right now. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@64124 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-28Rename getAnalysisToUpdate to getAnalysisIfAvailable.Duncan Sands
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63198 91177308-0d34-0410-b5e6-96231b3b80d8
2009-01-08Delete unnecessary parens around return values.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61950 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-10Add a newline after this debug output.Bill Wendling
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60861 91177308-0d34-0410-b5e6-96231b3b80d8
2008-12-03Add a sanity-check to tablegen to catch the case where isSimpleLoadDan Gohman
is set but mayLoad is not set. Fix all the problems this turned up. Change code to not use isSimpleLoad instead of mayLoad unless it really wants isSimpleLoad. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60459 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-27Increase default setting of tail-merge-threshold toDale Johannesen
150, based on llvm-test measurements. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58225 91177308-0d34-0410-b5e6-96231b3b80d8
2008-10-03Switch the MachineOperand accessors back to the short names likeDan Gohman
isReg, etc., from isRegister, etc. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@57006 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-22Mark several codegen passes as preserving all analysis.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56469 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-13Remove isImm(), isReg(), and friends, in favor of Dan Gohman
isImmediate(), isRegister(), and friends, to avoid confusion about having two different names with the same meaning. I'm not attached to the longer names, and would be ok with changing to the shorter names if others prefer it. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56189 91177308-0d34-0410-b5e6-96231b3b80d8
2008-09-04Tidy up several unbeseeming casts from pointer to intptr_t.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55779 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-22Fix SmallVector's size calculation so that a size of 0 isDan Gohman
handled correctly, and change a few SmallVector uses to use size 0 to more clearly reflect their intent. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@55181 91177308-0d34-0410-b5e6-96231b3b80d8
2008-08-14Convert uses of std::vector in TargetInstrInfo to SmallVector. This change ↵Owen Anderson
had to be propoagated down into all the targets and up into all clients of this API. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54802 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-29Fix PR2609. If a label is deleted, then it needsDuncan Sands
to be marked invalid regardless of whether it is a debug, an exception handling or (hopefully) a GC label. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54172 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-07Pool-allocation for MachineInstrs, MachineBasicBlocks, andDan Gohman
MachineMemOperands. The pools are owned by MachineFunctions. This drastically reduces the number of calls to malloc/free made during the "Emit" phase of scheduling, as well as later phases in CodeGen. Combined with other changes, this speeds up the "instruction selection" phase of CodeGen by 10% in some cases. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53212 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-01Fix longstanding thinko: don't excludeDale Johannesen
predessors of exit blocks from tail merging consideration. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52985 91177308-0d34-0410-b5e6-96231b3b80d8
2008-07-01Split ISD::LABEL into ISD::DBG_LABEL and ISD::EH_LABEL, eliminatingDan Gohman
the need for a flavor operand, and add a new SDNode subclass, LabelSDNode, for use with them to eliminate the need for a label id operand. Change instruction selection to let these label nodes through unmodified instead of creating copies of them. Teach the MachineInstr emitter how to emit a MachineInstr directly from an ISD label node. This avoids the need for allocating SDNodes for the label id and flavor value, as well as SDNodes for each of the post-isel label, label id, and label flavor. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52943 91177308-0d34-0410-b5e6-96231b3b80d8
2008-06-19Use the transferSuccessors helper function.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52495 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-23Rewrite a loop to avoid using iterators pointing toDale Johannesen
elements that have been erased. Based on a patch by Nicolas Capens. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51485 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-13Clean up the use of static and anonymous namespaces. This turned upDan Gohman
several things that were neither in an anonymous namespace nor static but not intended to be global. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51017 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-12Be more aggressive about tail-merging small blocksDale Johannesen
if those blocks consist entirely of common instructions; merging will not add an extra branch in this case. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@51006 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-12Further rework of tail merge algorithm. Not quiteDale Johannesen
semantically identical, but little difference in either results or execution speed; but it's much easier to read, at least IMO. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50999 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-09Remove an evil vector bool. Cosmetic refactoring,Dale Johannesen
no functional change. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50921 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-09Rewrite tail merging algorithm to handle theDale Johannesen
case where there are multiple blocks with a large number of common tail instructions more efficiently (compile time optimization). git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50916 91177308-0d34-0410-b5e6-96231b3b80d8
2008-05-06Make several variable declarations static.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50696 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-10Teach branch folding pass about implicit_def instructions. Unfortunately we ↵Evan Cheng
can't just eliminate them since register scavenger expects every register use to be defined. However, we can delete them when there are no intra-block uses. Carefully removing some implicit def's which enable more blocks to be optimized away. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@49461 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-28Add a quick and dirty "loop aligner pass". x86 uses it to align its loops to ↵Evan Cheng
16-byte boundaries. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47703 91177308-0d34-0410-b5e6-96231b3b80d8
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