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path: root/lib/CodeGen/BranchFolding.cpp
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2011-05-11Revert 131172 as it is causing clang to miscompile itself. I will tryRafael Espindola
to provide a reduced testcase. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131176 91177308-0d34-0410-b5e6-96231b3b80d8
2011-05-11Add a late optimization to BranchFolding that hoist common instruction sequencesEvan Cheng
at the start of basic blocks to their common predecessor. It's actually quite common (e.g. about 50 times in JM/lencod) and has shown to be a nice code size benefit. e.g. pushq %rax testl %edi, %edi jne LBB0_2 ## BB#1: xorb %al, %al popq %rdx ret LBB0_2: xorb %al, %al callq _foo popq %rdx ret => pushq %rax xorb %al, %al testl %edi, %edi je LBB0_2 ## BB#1: callq _foo LBB0_2: popq %rdx ret rdar://9145558 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131172 91177308-0d34-0410-b5e6-96231b3b80d8
2011-04-22Branch folding is folding a landing pad into a regular BB.Bill Wendling
An exception is thrown via a call to _cxa_throw, which we don't expect to return. Therefore, the "true" part of the invoke goes to a BB that has 'unreachable' as its only instruction. This is lowered into an empty MachineBB. The landing pad for this invoke, however, is directly after the "true" MBB. When the empty MBB is removed, the landing pad is directly below the BB with the invoke call. The unconditional branch is removed and then the two blocks are merged together. The testcase is too big for a regression test. <rdar://problem/9305728> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129965 91177308-0d34-0410-b5e6-96231b3b80d8
2011-02-21Add more debugging output.Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126158 91177308-0d34-0410-b5e6-96231b3b80d8
2010-08-06Reapply r110396, with fixes to appease the Linux buildbot gods.Owen Anderson
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 Anderson
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 Anderson
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
2010-06-22Tail merging pass shall not break up IT blocks. rdar://8115404Evan Cheng
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106517 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-18Allow ARM if-converter to be run after post allocation scheduling.Evan Cheng
- This fixed a number of bugs in if-converter, tail merging, and post-allocation scheduler. If-converter now runs branch folding / tail merging first to maximize if-conversion opportunities. - Also changed the t2IT instruction slightly. It now defines the ITSTATE register which is read by instructions in the IT block. - Added Thumb2 specific hazard recognizer to ensure the scheduler doesn't change the instruction ordering in the IT block (since IT mask has been finalized). It also ensures no other instructions can be scheduled between instructions in the IT block. This is not yet enabled. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106344 91177308-0d34-0410-b5e6-96231b3b80d8
2010-06-17Add a DebugLoc parameter to TargetInstrInfo::InsertBranch(). ThisStuart Hastings
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
2010-05-03Fix a bug which prevented tail merging of return instructions inDan Gohman
beneficial cases. See the changes in test/CodeGen/X86/tail-opts.ll and test/CodeGen/ARM/ifcvt2.ll for details. The fix is to change HashEndOfMBB to hash at most one instruction, instead of trying to apply heuristics about when it will be profitable to consider more than one instruction. The regular tail-merging heuristics are already prepared to handle the same cases, and they're more precise. Also, make test/CodeGen/ARM/ifcvt5.ll and test/CodeGen/Thumb2/thumb2-branch.ll slightly more complex so that they continue to test what they're intended to test. And, this eliminates the problem in test/CodeGen/Thumb2/2009-10-15-ITBlockBranch.ll, the testcase from PR5204. Update it accordingly. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@102907 91177308-0d34-0410-b5e6-96231b3b80d8
2010-04-02Teach AnalyzeBranch, RemoveBranch and the branchDale Johannesen
folder to be tolerant of debug info following the branch(es) at the end of a block. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100168 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-19Stop trying to merge identical jump tables. This had been inadvertentlyBob Wilson
disabled for several months (since svn r88806) and no one noticed. My fix for pr6543 yesterday reenabled it, but broke the ARM port's code for using TBB/TBH. Rather than adding a target hook to disable merging for Thumb2 only, I'm just taking this out. It is not common to have identical jump tables, the code we used to merge them was O(N^2), and it only helps code size, not performance. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98977 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-16Remove a check that can no longer be true, after r84803.Bob Wilson
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98694 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-14eliminate InvalidateLabel and LabelIDList from MMI and replaceChris Lattner
them with a counter. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98462 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-10Fix another place where DEBUG_VALUE affected codegen.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98181 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-10This survived a bootstrap, so let's try 98104 again.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98137 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-10Speculatively revert 98104; could be what's causing crashesDale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98108 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-09Ever more complicated DEBUG_VALUE fixes for branch folding.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98104 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-08Fix dbg value handling in tail merging.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97938 91177308-0d34-0410-b5e6-96231b3b80d8
2010-03-05Fix some more places where dbg_value affected codegen.Dale Johannesen
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97765 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-09move target-independent opcodes out of TargetInstrInfoChris Lattner
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
2010-01-25Rearrange handling of jump tables. Highlights:Chris Lattner
1. MachineJumpTableInfo is now created lazily for a function the first time it actually makes a jump table instead of for every function. 2. The encoding of jump table entries is now described by the MachineJumpTableInfo::JTEntryKind enum. This enum is determined by the TLI::getJumpTableEncoding() hook, instead of by lots of code scattered throughout the compiler that "knows" that jump table entries are always 32-bits in pic mode (for example). 3. The size and alignment of jump table entries is now calculated based on their kind, instead of at machinefunction creation time. Future work includes using the EntryKind in more places in the compiler, eliminating other logic that "knows" the layout of jump tables in various situations. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94470 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-24Change errs() to dbgs().David Greene
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92097 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-16Initialize uninitialized variables.Bill Wendling
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91477 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-16Initialize uninitialized variables.Bill Wendling
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91475 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-15Revert these. They may have been causing 483_xalancbmk to fail:Bill Wendling
$ svn merge -c -91161 https://llvm.org/svn/llvm-project/llvm/trunk --- Reverse-merging r91161 into '.': U lib/CodeGen/BranchFolding.cpp U lib/CodeGen/MachineBasicBlock.cpp $ svn merge -c -91113 https://llvm.org/svn/llvm-project/llvm/trunk --- Reverse-merging r91113 into '.': G lib/CodeGen/MachineBasicBlock.cpp $ svn merge -c -91101 https://llvm.org/svn/llvm-project/llvm/trunk --- Reverse-merging r91101 into '.': U include/llvm/CodeGen/MachineBasicBlock.h G lib/CodeGen/MachineBasicBlock.cpp $ svn merge -c -91092 https://llvm.org/svn/llvm-project/llvm/trunk --- Reverse-merging r91092 into '.': G include/llvm/CodeGen/MachineBasicBlock.h G lib/CodeGen/MachineBasicBlock.cpp git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91376 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-11Don't try to move a MBB into the fall-through position if it's a landing pad orBill Wendling
branches only to a landing pad. Without this check, the compiler would go into an infinite loop because the branch to a landing pad is an "abnormal" edge which wasn't being taken into account. This is the meat of that fix: if (!PrevBB.canFallThrough() && !MBB->BranchesToLandingPad(MBB)) { The other stuff is simplification of the "branches to a landing pad" code. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91161 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-05Remove the target hook TargetInstrInfo::BlockHasNoFallThrough in favor ofDan Gohman
MachineBasicBlock::canFallThrough(), which is target-independent and more thorough. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90634 91177308-0d34-0410-b5e6-96231b3b80d8
2009-12-03improve portability to avoid conflicting with std::next in c++'0x.Chris Lattner
Patch by Howard Hinnant! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90365 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-26Split tail duplication into a separate pass. This is needed to avoidBob Wilson
running tail duplication when doing branch folding for if-conversion, and we also want to be able to run tail duplication earlier to fix some reg alloc problems. Move the CanFallThrough function from BranchFolding to MachineBasicBlock so that it can be shared by TailDuplication. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89904 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-24Refactor target hook for tail duplication as requested by Chris.Bob Wilson
Make tail duplication of indirect branches much more aggressive (for targets that indicate that it is profitable), based on further experience with this transformation. I compiled 3 large applications with and without this more aggressive tail duplication and measured minimal changes in code size. ("size" on Darwin seems to round the text size up to the nearest page boundary, so I can only say that any code size increase was less than one 4k page.) Radar 7421267. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89814 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-18There should be no need to keep renumbering blocks during tail duplication.Bob Wilson
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89275 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-18Tail duplication still needs to iterate. Duplicating new instructions ontoBob Wilson
the tail of a block may make that block a new candidate for duplication. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89264 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-18Add another statistic to measure code size due to tail duplication.Bob Wilson
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89254 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-18Add statistics for tail duplication.Bob Wilson
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89225 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-18Add a target hook to allow changing the tail duplication limit based on theBob Wilson
contents of the block to be duplicated. Use this for ARM Cortex A8/9 to be more aggressive tail duplicating indirect branches, since it makes it much more likely that they will be predicted in the branch target buffer. Testcase coming soon. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89187 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-17Remove a special case for tail merging that seems to be both broken andBob Wilson
unnecessary. It is broken because the "isIdenticalTo" check should be negated. If that is fixed, this code causes the CodeGen/X86/tail-opts.ll test to fail, in the dont_merge_oddly function. And, I confirmed that the regression is real -- the generated code is worse. As far as I can tell, that tail-opts.ll test is checking for what this code is supposed to handle and we're doing the right thing anyway. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89121 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-17Set MadeChange instead of MadeChangeThisIteration.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89114 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-17Update a comment, now that tail duplication happens after other branchBob Wilson
folding optimizations. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89109 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-17Perform tail duplication only once, after tail merging is complete.Bob Wilson
It was too difficult to keep the heuristics for merging and duplication consistent. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89105 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-16Fix a comment.Bob Wilson
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88940 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-16Fix some comments.Bob Wilson
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88932 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-16Whitespace: be consistent with pointer syntax.Bob Wilson
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88929 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-16Clean up whitespace.Bob Wilson
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88927 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-13When optimizing for size, don't tail-merge unless it's likely to be aDan Gohman
code-size win, and not when it's only likely to be code-size neutral, such as when only a single instruction would be eliminated and a new branch would be required. This fixes rdar://7392894. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88692 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-12Make the BranchFolderPass class local to BranchFolding.cpp.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86928 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-12Minor code cleanups.Dan Gohman
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86926 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-12Tail merge at any size when there are two potentials blocks and oneDan Gohman
can be made to fall through into the other. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86909 91177308-0d34-0410-b5e6-96231b3b80d8
2009-11-11Promote MergePotentialsElt and SameTailElt to be regular classesDan Gohman
instead of typedefs for std::pair. This simplifies the type of SameTails, which previously was std::vector<std::pair<std::vector<std::pair<unsigned, MachineBasicBlock *> >::iterator, MachineBasicBlock::iterator> git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86885 91177308-0d34-0410-b5e6-96231b3b80d8
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