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path: root/llvm/lib/CodeGen/IfConversion.cpp
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2019-08-15Apply llvm-prefer-register-over-unsigned from clang-tidy to LLVMDaniel Sanders1-2/+2
Summary: This clang-tidy check is looking for unsigned integer variables whose initializer starts with an implicit cast from llvm::Register and changes the type of the variable to llvm::Register (dropping the llvm:: where possible). Partial reverts in: X86FrameLowering.cpp - Some functions return unsigned and arguably should be MCRegister X86FixupLEAs.cpp - Some functions return unsigned and arguably should be MCRegister X86FrameLowering.cpp - Some functions return unsigned and arguably should be MCRegister HexagonBitSimplify.cpp - Function takes BitTracker::RegisterRef which appears to be unsigned& MachineVerifier.cpp - Ambiguous operator==() given MCRegister and const Register PPCFastISel.cpp - No Register::operator-=() PeepholeOptimizer.cpp - TargetInstrInfo::optimizeLoadInstr() takes an unsigned& MachineTraceMetrics.cpp - MachineTraceMetrics lacks a suitable constructor Manual fixups in: ARMFastISel.cpp - ARMEmitLoad() now takes a Register& instead of unsigned& HexagonSplitDouble.cpp - Ternary operator was ambiguous between unsigned/Register HexagonConstExtenders.cpp - Has a local class named Register, used llvm::Register instead of Register. PPCFastISel.cpp - PPCEmitLoad() now takes a Register& instead of unsigned& Depends on D65919 Reviewers: arsenm, bogner, craig.topper, RKSimon Reviewed By: arsenm Subscribers: RKSimon, craig.topper, lenary, aemerson, wuzish, jholewinski, MatzeB, qcolombet, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, wdng, nhaehnle, sbc100, jgravelle-google, kristof.beyls, hiraditya, aheejin, kbarton, fedor.sergeev, javed.absar, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, tpr, PkmX, jocewei, jsji, Petar.Avramovic, asbirlea, Jim, s.egerton, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D65962 llvm-svn: 369041
2019-08-15[llvm] Migrate llvm::make_unique to std::make_uniqueJonas Devlieghere1-8/+8
Now that we've moved to C++14, we no longer need the llvm::make_unique implementation from STLExtras.h. This patch is a mechanical replacement of (hopefully) all the llvm::make_unique instances across the monorepo. llvm-svn: 369013
2019-04-23Use llvm::stable_sortFangrui Song1-1/+1
While touching the code, simplify if feasible. llvm-svn: 358996
2019-01-19Update the file headers across all of the LLVM projects in the monorepoChandler Carruth1-4/+3
to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351636
2019-01-09[NFC] fix trivial typos in commentsHiroshi Inoue1-2/+2
llvm-svn: 350690
2018-11-06LivePhysRegs/IfConversion: Change some types from unsigned to MCPhysReg; NFCMatthias Braun1-10/+10
Change the type in a couple of lists and sets that only store physical registers from unsigned to MCPhysRegs. The later is only 16bits and saves us a bit of memory. llvm-svn: 346254
2018-07-16[CodeGen] Fix inconsistent declaration parameter nameFangrui Song1-1/+1
llvm-svn: 337200
2018-05-14Rename DEBUG macro to LLVM_DEBUG.Nicola Zaghen1-26/+27
The DEBUG() macro is very generic so it might clash with other projects. The renaming was done as follows: - git grep -l 'DEBUG' | xargs sed -i 's/\bDEBUG\s\?(/LLVM_DEBUG(/g' - git diff -U0 master | ../clang/tools/clang-format/clang-format-diff.py -i -p1 -style LLVM - Manual change to APInt - Manually chage DOCS as regex doesn't match it. In the transition period the DEBUG() macro is still present and aliased to the LLVM_DEBUG() one. Differential Revision: https://reviews.llvm.org/D43624 llvm-svn: 332240
2018-05-09[DebugInfo] Examine all uses of isDebugValue() for debug instructions.Shiva Chen1-9/+9
Because we create a new kind of debug instruction, DBG_LABEL, we need to check all passes which use isDebugValue() to check MachineInstr is debug instruction or not. When expelling debug instructions, we should expel both DBG_VALUE and DBG_LABEL. So, I create a new function, isDebugInstr(), in MachineInstr to check whether the MachineInstr is debug instruction or not. This patch has no new test case. I have run regression test and there is no difference in regression test. Differential Revision: https://reviews.llvm.org/D45342 Patch by Hsiangkai Wang. llvm-svn: 331844
2018-04-19[if-converter] Handle BBs that terminate in ret during diamond conversionKrzysztof Parzyszek1-11/+28
This fixes https://llvm.org/PR36825. Original patch by Valentin Churavy (D45218). Differential Revision: https://reviews.llvm.org/D45731 llvm-svn: 330345
2018-04-08[TargetSchedule] shrink interface for init(); NFCISanjay Patel1-1/+1
The TargetSchedModel is always initialized using the TargetSubtargetInfo's MCSchedModel and TargetInstrInfo, so we don't need to extract those and pass 3 parameters to init(). Differential Revision: https://reviews.llvm.org/D44789 llvm-svn: 329540
2017-12-15MachineFunction: Return reference from getFunction(); NFCMatthias Braun1-1/+1
The Function can never be nullptr so we can return a reference. llvm-svn: 320884
2017-12-04[CodeGen] Unify MBB reference format in both MIR and debug outputFrancis Visoiu Mistrih1-16/+15
As part of the unification of the debug format and the MIR format, print MBB references as '%bb.5'. The MIR printer prints the IR name of a MBB only for block definitions. * find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#" << ([a-zA-Z0-9_]+)->getNumber\(\)/" << printMBBReference(*\1)/g' * find . \( -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#" << ([a-zA-Z0-9_]+)\.getNumber\(\)/" << printMBBReference(\1)/g' * find . \( -name "*.txt" -o -name "*.s" -o -name "*.mir" -o -name "*.cpp" -o -name "*.h" -o -name "*.ll" \) -type f -print0 | xargs -0 sed -i '' -E 's/BB#([0-9]+)/%bb.\1/g' * grep -nr 'BB#' and fix Differential Revision: https://reviews.llvm.org/D40422 llvm-svn: 319665
2017-11-17Fix a bunch more layering of CodeGen headers that are in TargetDavid Blaikie1-3/+3
All these headers already depend on CodeGen headers so moving them into CodeGen fixes the layering (since CodeGen depends on Target, not the other way around). llvm-svn: 318490
2017-11-08Target/TargetInstrInfo.h -> CodeGen/TargetInstrInfo.h to match layeringDavid Blaikie1-1/+1
This header includes CodeGen headers, and is not, itself, included by any Target headers, so move it into CodeGen to match the layering of its implementation. llvm-svn: 317647
2017-10-10CodeGen: Minor cleanups to use MachineInstr::getMF. NFCJustin Bogner1-3/+2
Since r315388 we have a shorter way to say this, so we'll replace MI->getParent()->getParent() with MI->getMF() in a few places. llvm-svn: 315390
2017-09-22[CodeGen] Fix some Clang-tidy modernize-use-default-member-init and Include ↵Eugene Zelenko1-20/+35
What You Use warnings; other minor fixes (NFC). llvm-svn: 314046
2017-09-14[IfConversion] More simple, correct dead/kill liveness handlingKrzysztof Parzyszek1-52/+3
Patch by Jesper Antonsson. Differential Revision: https://reviews.llvm.org/D37611 llvm-svn: 313268
2017-09-06[IfConversion] Remove kill flags from common instructions as wellKrzysztof Parzyszek1-4/+6
When if-converting a diamond, two separate blocks will be placed back to back to form a straight line code. To ensure correctness of the liveness information, any registers that are live in the second block should not be killed in the first block, even if they were in the original code. Additionally, when the two blocks share common instructions at the beginning, these instructions will not be duplicated, but only placed once, before both of the blocks. Since the function "isIdenticalTo" (as used here) ignores kill flags, the common initial code in one block may have a kill flag for a register that is live in the other block. Because the code that removes kill flags only runs for the non-common parts of the predicated blocks, a kill flag mismatch in the common code could still lead to a live register being killed prematurely. llvm-svn: 312654
2017-08-11[IfConversion] Maintain the CFG when predicating/merging blocks in IfConvert*Mikael Holmen1-38/+21
Summary: This fixes PR32721 in IfConvertTriangle and possible similar problems in IfConvertSimple, IfConvertDiamond and IfConvertForkedDiamond. In PR32721 we had a triangle EBB | \ | | | TBB | / FBB where FBB didn't have any successors at all since it ended with an unconditional return. Then TBB and FBB were be merged into EBB, but EBB would still keep its successors, and the use of analyzeBranch and CorrectExtraCFGEdges wouldn't help to remove them since the return instruction is not analyzable (at least not on ARM). The edge updating code and branch probability updating code is now pushed into MergeBlocks() which allows us to share the same update logic between more callsites. This lets us remove several dependencies on analyzeBranch and completely eliminate RemoveExtraEdges. One thing that showed up with this patch was that IfConversion sometimes left a successor with 0% probability even if there was no branch or fallthrough to the successor. One such example from the test case ifcvt_bad_zero_prob_succ.mir. The indirect branch tBRIND can only jump to bb.1, but without the patch we got: bb.0: successors: %bb.1(0x80000000) bb.1: successors: %bb.1(0x80000000), %bb.2(0x00000000) tBRIND %r1, 1, %cpsr B %bb.1 bb.2: There is no way to jump from bb.1 to bb2, but still there is a 0% edge from bb.1 to bb.2. With the patch applied we instead get the expected: bb.0: successors: %bb.1(0x80000000) bb.1: successors: %bb.1(0x80000000) tBRIND %r1, 1, %cpsr B %bb.1 Since bb.2 had no predecessor at all, it was removed. Several testcases had to be updated due to this since the removed successor made the "Branch Probability Basic Block Placement" pass sometimes place blocks in a different order. Finally added a couple of new test cases: * PR32721_ifcvt_triangle_unanalyzable.mir: Regression test for the original problem dexcribed in PR 32721. * ifcvt_triangleWoCvtToNextEdge.mir: Regression test for problem that caused a revert of my first attempt to solve PR 32721. * ifcvt_simple_bad_zero_prob_succ.mir: Test case showing the problem where a wrong successor with 0% probability was previously left. * ifcvt_[diamond|forked_diamond|simple]_unanalyzable.mir Very simple test cases for the simple and (forked) diamond cases involving unanalyzable branches that can be nice to have as a base if wanting to write more complicated tests. Reviewers: iteratee, MatzeB, grosser, kparzysz Reviewed By: kparzysz Subscribers: kbarton, davide, aemerson, nemanjai, javed.absar, kristof.beyls, llvm-commits Differential Revision: https://reviews.llvm.org/D34099 llvm-svn: 310697
2017-06-26[IfConversion] Hoist removeBranch calls out of if/else clauses [NFC]Mikael Holmen1-4/+9
Summary: Also added a comment. Pulled out of https://reviews.llvm.org/D34099. Reviewers: iteratee Reviewed By: iteratee Subscribers: llvm-commits Differential Revision: https://reviews.llvm.org/D34388 llvm-svn: 306279
2017-06-06Sort the remaining #include lines in include/... and lib/....Chandler Carruth1-1/+1
I did this a long time ago with a janky python script, but now clang-format has built-in support for this. I fed clang-format every line with a #include and let it re-sort things according to the precise LLVM rules for include ordering baked into clang-format these days. I've reverted a number of files where the results of sorting includes isn't healthy. Either places where we have legacy code relying on particular include ordering (where possible, I'll fix these separately) or where we have particular formatting around #include lines that I didn't want to disturb in this patch. This patch is *entirely* mechanical. If you get merge conflicts or anything, just ignore the changes in this patch and run clang-format over your #include lines in the files. Sorry for any noise here, but it is important to keep these things stable. I was seeing an increasing number of patches with irrelevant re-ordering of #include lines because clang-format was used. This patch at least isolates that churn, makes it easy to skip when resolving conflicts, and gets us to a clean baseline (again). llvm-svn: 304787
2017-05-29Revert "[IfConversion] Keep the CFG updated incrementally in IfConvertTriangle"Tobias Grosser1-21/+6
The reverted change introdued assertions ala: "MachineBasicBlock::succ_iterator llvm::MachineBasicBlock::removeSuccessor(succ_iterator, bool): Assertion `I != Successors.end() && "Not a current successor!"' Mikael, the original committer, wrote me that he is working on a fix, but that it likely will take some time to get this resolved. As this bug is one of the last two issues that keep the AOSP buildbot from turning green, I revert the original commit r302876. I am looking forward to see this recommitted after the assertion has been resolved. llvm-svn: 304128
2017-05-25CodeGen: Rename DEBUG_TYPE to match passnamesMatthias Braun1-3/+3
Rename the DEBUG_TYPE to match the names of corresponding passes where it makes sense. Also establish the pattern of simply referencing DEBUG_TYPE instead of repeating the passname where possible. llvm-svn: 303921
2017-05-12[IfConversion] Keep the CFG updated incrementally in IfConvertTriangleMikael Holmen1-6/+21
Summary: Instead of using RemoveExtraEdges (which uses analyzeBranch, which cannot always be trusted) at the end to fixup the CFG we keep the CFG updated as we go along and remove or add branches and merge blocks. This way we won't have any problems if the involved MBBs contain unanalyzable instructions. This fixes PR32721. In that case we had a triangle EBB | \ | | | TBB | / FBB where FBB didn't have any successors at all since it ended with an unconditional return. Then TBB and FBB were be merged into EBB, but EBB would still keep its successors, and the use of analyzeBranch and CorrectExtraCFGEdges wouldn't help to remove them since the return instruction is not analyzable (at least not on ARM). Reviewers: kparzysz, iteratee, MatzeB Reviewed By: iteratee Subscribers: aemerson, rengolin, javed.absar, llvm-commits Differential Revision: https://reviews.llvm.org/D33037 llvm-svn: 302876
2017-05-10[IfConversion] Add missing check in IfConversion/canFallThroughToMikael Holmen1-1/+2
Summary: When trying to figure out if MBB could fallthrough to ToMBB (possibly by falling through a bunch of other MBBs) we didn't actually check if there was fallthrough between the last two blocks in the chain. Reviewers: kparzysz, iteratee, MatzeB Reviewed By: kparzysz, iteratee Subscribers: javed.absar, llvm-commits Differential Revision: https://reviews.llvm.org/D32996 llvm-svn: 302650
2017-03-06[IfConversion] Only renormalize probabilities if branches are analyzableKrzysztof Parzyszek1-2/+4
If a block has non-analyzable branches, the listed successors don't need to add up to one. For example, if a block has a conditional tail call, that tail call will not have a corresponding successor in the successor list, but will still be a possible branch. Differential Revision: https://reviews.llvm.org/D30556 llvm-svn: 297054
2017-01-26[IfConversion] Use reverse_iterator to simplify. NFCKyle Butt1-70/+35
This simplifies skipping debug instructions and shrinking ranges. llvm-svn: 293202
2017-01-05CodeGen: Assert that liveness is up to date when reading block live-ins.Matthias Braun1-17/+25
Add an assert that checks whether liveins are up to date before they are used. - Do not print liveins into .mir files anymore in situations where they are out of date anyway. - The assert in the RegisterScavenger is superseded by the new one in livein_begin(). - Skip parts of the liveness updating logic in IfConversion.cpp when liveness isn't tracked anymore (just enough to avoid hitting the new assert()). Differential Revision: https://reviews.llvm.org/D27562 llvm-svn: 291169
2016-12-16 [codegen] Add generic functions to skip debug values.Florian Hahn1-34/+14
Summary: This commits moves skipDebugInstructionsForward and skipDebugInstructionsBackward from lib/CodeGen/IfConversion.cpp to include/llvm/CodeGen/MachineBasicBlock.h and updates some codgen files to use them. This refactoring was suggested in https://reviews.llvm.org/D27688 and I thought it's best to do the refactoring in a separate review, but I could also put both changes in a single review if that's preferred. Also, the names for the functions aren't the snappiest and I would be happy to rename them if anybody has suggestions. Reviewers: eli.friedman, iteratee, aprantl, MatzeB Subscribers: MatzeB, llvm-commits Differential Revision: https://reviews.llvm.org/D27782 llvm-svn: 289933
2016-12-08LivePhysReg: Use reference instead of pointer in init(); NFCMatthias Braun1-5/+5
llvm-svn: 289002
2016-10-24CodeGen/Passes: Pass MachineFunction as functor arg; NFCMatthias Braun1-5/+4
Passing a MachineFunction as argument is more natural and avoids an unnecessary round-trip through the logic determining the correct Subtarget because MachineFunction already has a reference anyway. llvm-svn: 285039
2016-09-28IfConversion: Add implicit uses for redefined regs with live subregistersKrzysztof Parzyszek1-0/+11
Normally, if conversion would add implicit uses for redefined registers, e.g. R0<def> = add_if ..., R0<imp-use>. However, if only subregisters of R0 are known to be live but not R0 itself, such implicit uses will not be added, causing prior definitions of such subregisters and R0 itself to become dead. llvm-svn: 282626
2016-09-14Finish renaming remaining analyzeBranch functionsMatt Arsenault1-23/+23
llvm-svn: 281535
2016-09-14Make analyzeBranch family of instruction names consistentMatt Arsenault1-4/+4
analyzeBranch was renamed to use lowercase first, rename the related set to match. llvm-svn: 281506
2016-09-11CodeGen: Give MachineBasicBlock::reverse_iterator a handle to the current MIDuncan P. N. Exon Smith1-2/+1
Now that MachineBasicBlock::reverse_instr_iterator knows when it's at the end (since r281168 and r281170), implement MachineBasicBlock::reverse_iterator directly on top of an ilist::reverse_iterator by adding an IsReverse template parameter to MachineInstrBundleIterator. This replaces another hard-to-reason-about use of std::reverse_iterator on list iterators, matching the changes for ilist::reverse_iterator from r280032 (see the "out of scope" section at the end of that commit message). MachineBasicBlock::reverse_iterator now has a handle to the current node and has obvious invalidation semantics. r280032 has a more detailed explanation of how list-style reverse iterators (invalidated when the pointed-at node is deleted) are different from vector-style reverse iterators like std::reverse_iterator (invalidated on every operation). A great motivating example is this commit's changes to lib/CodeGen/DeadMachineInstructionElim.cpp. Note: If your out-of-tree backend deletes instructions while iterating on a MachineBasicBlock::reverse_iterator or converts between MachineBasicBlock::iterator and MachineBasicBlock::reverse_iterator, you'll need to update your code in similar ways to r280032. The following table might help: [Old] ==> [New] delete &*RI, RE = end() delete &*RI++ RI->erase(), RE = end() RI++->erase() reverse_iterator(I) std::prev(I).getReverse() reverse_iterator(I) ++I.getReverse() --reverse_iterator(I) I.getReverse() reverse_iterator(std::next(I)) I.getReverse() RI.base() std::prev(RI).getReverse() RI.base() ++RI.getReverse() --RI.base() RI.getReverse() std::next(RI).base() RI.getReverse() (For more details, have a look at r280032.) llvm-svn: 281172
2016-09-02IfConversion: Add assertions that both sides of a diamond don't pred-clobber.Kyle Butt1-2/+3
One side of a diamond may end with a predicate clobbering instruction. That side of the diamond has to be if-converted second. Both sides can't clobber the predicate or the ifconversion is invalid. This is checked elsewhere, but add an assert as a safety check. NFC llvm-svn: 280518
2016-09-02IfConversion: Fix bug introduced by rescanning diamonds.Kyle Butt1-1/+1
Passing the wrong values for predicate-clobbering. Simple to miss. Added an assert to make this easier to catch in the future. llvm-svn: 280517
2016-09-02IfConversion: Don't count branches in # of duplicates.Kyle Butt1-1/+3
If the entire blocks match, we would count the branch instructions toward the number of duplicated instructions. This doesn't match what we do elsewhere, and was causing a bug. llvm-svn: 280448
2016-08-29IfConversion: Fix branch predication bug.Kyle Butt1-20/+61
This bug shows up with diamonds that share unpredicable, unanalyzable branches. There's an included test case from Hexagon. What was happening was that we were attempting to predicate the branch instruction despite the fact that it was checked to be the same. Now for unanalyzable branches we skip over the branch instructions when predicating the block. Differential Revision: https://reviews.llvm.org/D23939 llvm-svn: 279985
2016-08-25MachineFunctionProperties/MIRParser: Rename AllVRegsAllocated->NoVRegs, ↵Matthias Braun1-1/+1
compute it Rename AllVRegsAllocated to NoVRegs. This avoids the connotation of running after register and simply describes that no vregs are used in a machine function. With that we can simply compute the property and do not need to dump/parse it in .mir files. Differential Revision: http://reviews.llvm.org/D23850 llvm-svn: 279698
2016-08-24CodeGen: If Convert blocks that would form a diamond when tail-merged.Kyle Butt1-74/+277
The following function currently relies on tail-merging for if conversion to succeed. The common tail of cond_true and cond_false is extracted, and this then forms a diamond pattern that can be successfully if converted. If this block does not get extracted, either because tail-merging is disabled or the threshold is higher, we should still recognize this pattern and if-convert it. Fixed a regression in the original commit. Need to un-reverse branches after reversing them, or other conversions go awry. define i32 @t2(i32 %a, i32 %b) nounwind { entry: %tmp1434 = icmp eq i32 %a, %b ; <i1> [#uses=1] br i1 %tmp1434, label %bb17, label %bb.outer bb.outer: ; preds = %cond_false, %entry %b_addr.021.0.ph = phi i32 [ %b, %entry ], [ %tmp10, %cond_false ] %a_addr.026.0.ph = phi i32 [ %a, %entry ], [ %a_addr.026.0, %cond_false ] br label %bb bb: ; preds = %cond_true, %bb.outer %indvar = phi i32 [ 0, %bb.outer ], [ %indvar.next, %cond_true ] %tmp. = sub i32 0, %b_addr.021.0.ph %tmp.40 = mul i32 %indvar, %tmp. %a_addr.026.0 = add i32 %tmp.40, %a_addr.026.0.ph %tmp3 = icmp sgt i32 %a_addr.026.0, %b_addr.021.0.ph br i1 %tmp3, label %cond_true, label %cond_false cond_true: ; preds = %bb %tmp7 = sub i32 %a_addr.026.0, %b_addr.021.0.ph %tmp1437 = icmp eq i32 %tmp7, %b_addr.021.0.ph %indvar.next = add i32 %indvar, 1 br i1 %tmp1437, label %bb17, label %bb cond_false: ; preds = %bb %tmp10 = sub i32 %b_addr.021.0.ph, %a_addr.026.0 %tmp14 = icmp eq i32 %a_addr.026.0, %tmp10 br i1 %tmp14, label %bb17, label %bb.outer bb17: ; preds = %cond_false, %cond_true, %entry %a_addr.026.1 = phi i32 [ %a, %entry ], [ %tmp7, %cond_true ], [ %a_addr.026.0, %cond_false ] ret i32 %a_addr.026.1 } Without tail-merging or diamond-tail if conversion: LBB1_1: @ %bb @ =>This Inner Loop Header: Depth=1 cmp r0, r1 ble LBB1_3 @ BB#2: @ %cond_true @ in Loop: Header=BB1_1 Depth=1 subs r0, r0, r1 cmp r1, r0 it ne cmpne r0, r1 bgt LBB1_4 LBB1_3: @ %cond_false @ in Loop: Header=BB1_1 Depth=1 subs r1, r1, r0 cmp r1, r0 bne LBB1_1 LBB1_4: @ %bb17 bx lr With diamond-tail if conversion, but without tail-merging: @ BB#0: @ %entry cmp r0, r1 it eq bxeq lr LBB1_1: @ %bb @ =>This Inner Loop Header: Depth=1 cmp r0, r1 ite le suble r1, r1, r0 subgt r0, r0, r1 cmp r1, r0 bne LBB1_1 @ BB#2: @ %bb17 bx lr llvm-svn: 279671
2016-08-24IfConversion: Rescan diamonds.Kyle Butt1-52/+162
The cost of predicating a diamond is only the instructions that are not shared between the two branches. Additionally If a predicate clobbering instruction occurs in the shared portion of the branches (e.g. a cond move), it may still be possible to if convert the sub-cfg. This change handles these two facts by rescanning the non-shared portion of a diamond sub-cfg to recalculate both the predication cost and whether both blocks are pred-clobbering. Fixed 2 bugs before recommitting. Branch instructions must be compared and found identical before diamond conversion. Also, predicate-clobbering instructions in the shared prefix disqualifies a potential diamond conversion. Includes tests for both. llvm-svn: 279670
2016-08-19Revert "IfConversion: Rescan diamonds."Kyle Butt1-115/+34
This reverts commit bfd62a4b4465dd21811bf615c3b04c30ddb09f7b. llvm-svn: 279289
2016-08-19Revert "CodeGen: If Convert blocks that would form a diamond when tail-merged."Kyle Butt1-287/+78
This reverts commit 0fda93481c4231c06b838ef476c0c404c51ff875. llvm-svn: 279288
2016-08-18CodeGen: If Convert blocks that would form a diamond when tail-merged.Kyle Butt1-78/+287
The following function currently relies on tail-merging for if conversion to succeed. The common tail of cond_true and cond_false is extracted, and this then forms a diamond pattern that can be successfully if converted. If this block does not get extracted, either because tail-merging is disabled or the threshold is higher, we should still recognize this pattern and if-convert it. Fixed a regression in the original commit. Need to un-reverse branches after reversing them, or other conversions go awry. Regression on self-hosting bots with no obvious explanation. Tidied up range handling to be more obviously correct, but there was no smoking gun. define i32 @t2(i32 %a, i32 %b) nounwind { entry: %tmp1434 = icmp eq i32 %a, %b ; <i1> [#uses=1] br i1 %tmp1434, label %bb17, label %bb.outer bb.outer: ; preds = %cond_false, %entry %b_addr.021.0.ph = phi i32 [ %b, %entry ], [ %tmp10, %cond_false ] %a_addr.026.0.ph = phi i32 [ %a, %entry ], [ %a_addr.026.0, %cond_false ] br label %bb bb: ; preds = %cond_true, %bb.outer %indvar = phi i32 [ 0, %bb.outer ], [ %indvar.next, %cond_true ] %tmp. = sub i32 0, %b_addr.021.0.ph %tmp.40 = mul i32 %indvar, %tmp. %a_addr.026.0 = add i32 %tmp.40, %a_addr.026.0.ph %tmp3 = icmp sgt i32 %a_addr.026.0, %b_addr.021.0.ph br i1 %tmp3, label %cond_true, label %cond_false cond_true: ; preds = %bb %tmp7 = sub i32 %a_addr.026.0, %b_addr.021.0.ph %tmp1437 = icmp eq i32 %tmp7, %b_addr.021.0.ph %indvar.next = add i32 %indvar, 1 br i1 %tmp1437, label %bb17, label %bb cond_false: ; preds = %bb %tmp10 = sub i32 %b_addr.021.0.ph, %a_addr.026.0 %tmp14 = icmp eq i32 %a_addr.026.0, %tmp10 br i1 %tmp14, label %bb17, label %bb.outer bb17: ; preds = %cond_false, %cond_true, %entry %a_addr.026.1 = phi i32 [ %a, %entry ], [ %tmp7, %cond_true ], [ %a_addr.026.0, %cond_false ] ret i32 %a_addr.026.1 } Without tail-merging or diamond-tail if conversion: LBB1_1: @ %bb @ =>This Inner Loop Header: Depth=1 cmp r0, r1 ble LBB1_3 @ BB#2: @ %cond_true @ in Loop: Header=BB1_1 Depth=1 subs r0, r0, r1 cmp r1, r0 it ne cmpne r0, r1 bgt LBB1_4 LBB1_3: @ %cond_false @ in Loop: Header=BB1_1 Depth=1 subs r1, r1, r0 cmp r1, r0 bne LBB1_1 LBB1_4: @ %bb17 bx lr With diamond-tail if conversion, but without tail-merging: @ BB#0: @ %entry cmp r0, r1 it eq bxeq lr LBB1_1: @ %bb @ =>This Inner Loop Header: Depth=1 cmp r0, r1 ite le suble r1, r1, r0 subgt r0, r0, r1 cmp r1, r0 bne LBB1_1 @ BB#2: @ %bb17 bx lr llvm-svn: 279168
2016-08-18IfConversion: Rescan diamonds.Kyle Butt1-34/+115
The cost of predicating a diamond is only the instructions that are not shared between the two branches. Additionally If a predicate clobbering instruction occurs in the shared portion of the branches (e.g. a cond move), it may still be possible to if convert the sub-cfg. This change handles these two facts by rescanning the non-shared portion of a diamond sub-cfg to recalculate both the predication cost and whether both blocks are pred-clobbering. llvm-svn: 279167
2016-08-18IfConversion: Handle inclusive ranges more carefully.Kyle Butt1-22/+56
This may affect calculations for thresholds, but is not a significant change in behavior. The problem was that an inclusive range must have an additonal flag to showr that it is empty, because otherwise begin == end implies that the range has one element, and it may not be possible to move past on either side. llvm-svn: 279166
2016-08-17IfConversion: Use references instead of pointers where possible; NFCMatthias Braun1-124/+134
Also put some commonly used subexpressions into variables. llvm-svn: 278895
2016-08-17IfConversion: Use range based for; NFCMatthias Braun1-35/+23
Also avoid some pointless use of auto! Because that's friendlier to readers and avoids several types accidentally resolving to unnecessary references here (MachineInstr *&, unsigned &). llvm-svn: 278894
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