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* Fix a bug which prevented tail merging of return instructions inDan Gohman2010-05-031-24/+5
| | | | | | | | | | | | | | | | | | | | | 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
* Teach AnalyzeBranch, RemoveBranch and the branchDale Johannesen2010-04-021-3/+9
| | | | | | | | | 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
* Stop trying to merge identical jump tables. This had been inadvertentlyBob Wilson2010-03-191-28/+6
| | | | | | | | | | | | 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
* Remove a check that can no longer be true, after r84803.Bob Wilson2010-03-161-16/+0
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98694 91177308-0d34-0410-b5e6-96231b3b80d8
* eliminate InvalidateLabel and LabelIDList from MMI and replaceChris Lattner2010-03-141-11/+0
| | | | | | | them with a counter. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98462 91177308-0d34-0410-b5e6-96231b3b80d8
* Fix another place where DEBUG_VALUE affected codegen.Dale Johannesen2010-03-101-1/+12
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98181 91177308-0d34-0410-b5e6-96231b3b80d8
* This survived a bootstrap, so let's try 98104 again.Dale Johannesen2010-03-101-4/+69
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98137 91177308-0d34-0410-b5e6-96231b3b80d8
* Speculatively revert 98104; could be what's causing crashesDale Johannesen2010-03-101-56/+3
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98108 91177308-0d34-0410-b5e6-96231b3b80d8
* Ever more complicated DEBUG_VALUE fixes for branch folding.Dale Johannesen2010-03-091-3/+56
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@98104 91177308-0d34-0410-b5e6-96231b3b80d8
* Fix dbg value handling in tail merging.Dale Johannesen2010-03-081-3/+25
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97938 91177308-0d34-0410-b5e6-96231b3b80d8
* Fix some more places where dbg_value affected codegen.Dale Johannesen2010-03-051-1/+5
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97765 91177308-0d34-0410-b5e6-96231b3b80d8
* move target-independent opcodes out of TargetInstrInfoChris Lattner2010-02-091-2/+2
| | | | | | | | | | 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
* Rearrange handling of jump tables. Highlights:Chris Lattner2010-01-251-44/+49
| | | | | | | | | | | | | | | | | | | | 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
* Change errs() to dbgs().David Greene2009-12-241-13/+13
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@92097 91177308-0d34-0410-b5e6-96231b3b80d8
* Initialize uninitialized variables.Bill Wendling2009-12-161-1/+1
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91477 91177308-0d34-0410-b5e6-96231b3b80d8
* Initialize uninitialized variables.Bill Wendling2009-12-161-1/+1
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@91475 91177308-0d34-0410-b5e6-96231b3b80d8
* Revert these. They may have been causing 483_xalancbmk to fail:Bill Wendling2009-12-151-23/+19
| | | | | | | | | | | | | | | | | | | | | | $ 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
* Don't try to move a MBB into the fall-through position if it's a landing pad orBill Wendling2009-12-111-19/+23
| | | | | | | | | | | | | | | 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
* Remove the target hook TargetInstrInfo::BlockHasNoFallThrough in favor ofDan Gohman2009-12-051-1/+1
| | | | | | | | 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
* improve portability to avoid conflicting with std::next in c++'0x.Chris Lattner2009-12-031-4/+4
| | | | | | | Patch by Howard Hinnant! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90365 91177308-0d34-0410-b5e6-96231b3b80d8
* Split tail duplication into a separate pass. This is needed to avoidBob Wilson2009-11-261-231/+6
| | | | | | | | | | 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
* Refactor target hook for tail duplication as requested by Chris.Bob Wilson2009-11-241-3/+12
| | | | | | | | | | | | | 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
* There should be no need to keep renumbering blocks during tail duplication.Bob Wilson2009-11-181-3/+0
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89275 91177308-0d34-0410-b5e6-96231b3b80d8
* Tail duplication still needs to iterate. Duplicating new instructions ontoBob Wilson2009-11-181-3/+7
| | | | | | | 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
* Add another statistic to measure code size due to tail duplication.Bob Wilson2009-11-181-0/+3
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89254 91177308-0d34-0410-b5e6-96231b3b80d8
* Add statistics for tail duplication.Bob Wilson2009-11-181-0/+4
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89225 91177308-0d34-0410-b5e6-96231b3b80d8
* Add a target hook to allow changing the tail duplication limit based on theBob Wilson2009-11-181-4/+5
| | | | | | | | | | 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
* Remove a special case for tail merging that seems to be both broken andBob Wilson2009-11-171-33/+0
| | | | | | | | | | | | 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
* Set MadeChange instead of MadeChangeThisIteration.Dan Gohman2009-11-171-1/+1
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89114 91177308-0d34-0410-b5e6-96231b3b80d8
* Update a comment, now that tail duplication happens after other branchBob Wilson2009-11-171-2/+2
| | | | | | | folding optimizations. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@89109 91177308-0d34-0410-b5e6-96231b3b80d8
* Perform tail duplication only once, after tail merging is complete.Bob Wilson2009-11-171-30/+66
| | | | | | | | 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
* Fix a comment.Bob Wilson2009-11-161-1/+1
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88940 91177308-0d34-0410-b5e6-96231b3b80d8
* Fix some comments.Bob Wilson2009-11-161-5/+4
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88932 91177308-0d34-0410-b5e6-96231b3b80d8
* Whitespace: be consistent with pointer syntax.Bob Wilson2009-11-161-6/+6
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88929 91177308-0d34-0410-b5e6-96231b3b80d8
* Clean up whitespace.Bob Wilson2009-11-161-6/+6
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@88927 91177308-0d34-0410-b5e6-96231b3b80d8
* When optimizing for size, don't tail-merge unless it's likely to be aDan Gohman2009-11-131-9/+12
| | | | | | | | | | | 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
* Make the BranchFolderPass class local to BranchFolding.cpp.Dan Gohman2009-11-121-0/+14
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86928 91177308-0d34-0410-b5e6-96231b3b80d8
* Minor code cleanups.Dan Gohman2009-11-121-9/+9
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86926 91177308-0d34-0410-b5e6-96231b3b80d8
* Tail merge at any size when there are two potentials blocks and oneDan Gohman2009-11-121-10/+34
| | | | | | | 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
* Promote MergePotentialsElt and SameTailElt to be regular classesDan Gohman2009-11-111-56/+58
| | | | | | | | 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
* Revert this line of 86871.Dan Gohman2009-11-111-1/+1
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86875 91177308-0d34-0410-b5e6-96231b3b80d8
* Add support for tail duplication to BranchFolding, and extendDan Gohman2009-11-111-49/+295
| | | | | | | | | | | | 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
* Fix indentation level.Dan Gohman2009-11-111-8/+8
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86856 91177308-0d34-0410-b5e6-96231b3b80d8
* Whitespace cleanups.Dan Gohman2009-11-111-93/+92
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* Prefix MBB numbers with "BB#" in debug output to make it clear whatDan Gohman2009-11-111-3/+3
| | | | | | | the numbers mean. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86854 91177308-0d34-0410-b5e6-96231b3b80d8
* Minor code simplification.Dan Gohman2009-11-111-9/+8
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86853 91177308-0d34-0410-b5e6-96231b3b80d8
* Remove an unused variable.Dan Gohman2009-11-101-1/+0
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86642 91177308-0d34-0410-b5e6-96231b3b80d8
* Minor code simplification.Dan Gohman2009-11-101-1/+1
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86641 91177308-0d34-0410-b5e6-96231b3b80d8
* Fix branch folding bug for indirect branches: for a block containing onlyBob Wilson2009-11-031-1/+2
| | | | | | | | | | | | | | | | 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
* Don't delete blocks which have their address taken.Dan Gohman2009-10-301-2/+3
| | | | git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85572 91177308-0d34-0410-b5e6-96231b3b80d8
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