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llvm-project/llvm/test/Transforms/SimplifyCFG
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James Molloy 88cad7e5cf [SimplifyCFG] Handle tail-sinking of more than 2 incoming branches 
This was a real restriction in the original version of SinkIfThenCodeToEnd. Now it's been rewritten, the restriction can be lifted.

As part of this, we handle a very common and useful case where one of the incoming branches is actually conditional. Consider:

   if (a)
     x(1);
   else if (b)
     x(2);

This produces the following CFG:

         [if]
        /    \
      [x(1)] [if]
        |     | \
        |     |  \
        |  [x(2)] |
         \    |  /
          [ end ]

[end] has two unconditional predecessor arcs and one conditional. The conditional refers to the implicit empty 'else' arc. This same pattern can also be caused by an empty default block in a switch.

We can't sink the call to x() down to end because no call to x() happens on the third incoming arc (assume that x() has sideeffects for the sake of argument; if something is safe to speculate we could indeed sink nevertheless but this cannot happen in the general case and causes many extra selects).

We are now able to detect this case and split off the unconditional arcs to a common successor:

         [if]
        /    \
      [x(1)] [if]
        |     | \
        |     |  \
        |  [x(2)] |
         \   /    |
     [sink.split] |
           \     /
           [ end ]

Now we can sink the call to x() into %sink.split. This can cause significant code simplification in many testcases.

llvm-svn: 280364
 		2016-09-01 12:58:13 +00:00
..
AArch64 [SimplifyCFG] Rewrite SinkThenElseCodeToEnd 2016-08-22 19:07:15 +00:00
AMDGPU AMDGPU: Fix some places missed in rename 2015-06-19 17:39:03 +00:00
ARM [ARM] add overrides for isCheapToSpeculateCttz() and isCheapToSpeculateCtlz() 2015-11-10 19:24:31 +00:00
Mips [MIPS] add overrides for isCheapToSpeculateCttz() and isCheapToSpeculateCtlz() 2015-11-11 17:24:56 +00:00
PowerPC [CodeGenPrepare] Removed duplicate logic. SimplifyCFG already knows how to speculate calls to cttz/ctlz. 2015-02-13 14:15:48 +00:00
SPARC
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X86 [SimlifyCFG] Prevent passes from destroying canonical loop structure, especially for nested loops 2016-03-29 04:08:57 +00:00
2002-05-21-PHIElimination.ll
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2002-09-24-PHIAssertion.ll
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2003-03-07-DominateProblem.ll
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2003-08-05-InvokeCrash.ll Move the personality function from LandingPadInst to Function 2015-06-17 20:52:32 +00:00
2003-08-17-BranchFold.ll
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2003-08-17-BranchFoldOrdering.ll
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2003-08-17-FoldSwitch-dbg.ll [opaque pointer type] Add textual IR support for explicit type parameter to gep operator 2015-03-13 18:20:45 +00:00
2003-08-17-FoldSwitch.ll regenerate checks 2016-03-28 22:12:21 +00:00
2004-12-10-SimplifyCFGCrash.ll
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2005-06-16-PHICrash.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2005-08-01-PHIUpdateFail.ll [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction 2015-02-27 19:29:02 +00:00
2005-10-02-InvokeSimplify.ll Move the personality function from LandingPadInst to Function 2015-06-17 20:52:32 +00:00
2005-12-03-IncorrectPHIFold.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2006-02-17-InfiniteUnroll.ll
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2006-06-12-InfLoop.ll
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2006-08-03-Crash.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2006-10-19-UncondDiv.ll
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2006-12-08-Ptr-ICmp-Branch.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2007-11-22-InvokeNoUnwind.ll Move the personality function from LandingPadInst to Function 2015-06-17 20:52:32 +00:00
2007-12-21-Crash.ll [opaque pointer type] Add textual IR support for explicit type parameter to the call instruction 2015-04-16 23:24:18 +00:00
2008-01-02-hoist-fp-add.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2008-05-16-PHIBlockMerge.ll [SimlifyCFG] Prevent passes from destroying canonical loop structure, especially for nested loops 2016-03-29 04:08:57 +00:00
2008-07-13-InfLoopMiscompile.ll remove the metadata added with r267827 2016-04-30 00:02:36 +00:00
2008-09-08-MultiplePred.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2008-09-17-SpeculativeHoist.ll
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2008-10-03-SpeculativelyExecuteBeforePHI.ll
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2008-12-06-SingleEntryPhi.ll
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2008-12-16-DCECond.ll [opaque pointer type] Add textual IR support for explicit type parameter to the call instruction 2015-04-16 23:24:18 +00:00
2009-01-18-PHIPropCrash.ll
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2009-05-12-externweak.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
2010-03-30-InvokeCrash.ll Move the personality function from LandingPadInst to Function 2015-06-17 20:52:32 +00:00
2011-03-08-UnreachableUse.ll
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2011-09-05-TrivialLPad.ll Move the personality function from LandingPadInst to Function 2015-06-17 20:52:32 +00:00
BrUnwind.ll
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ConditionalTrappingConstantExpr.ll [Constant] remove fdiv and frem from canTrap() 2016-08-29 15:27:17 +00:00
CoveredLookupTable.ll
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DeadSetCC.ll
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EmptyBlockMerge.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
EqualPHIEdgeBlockMerge.ll [SimlifyCFG] Prevent passes from destroying canonical loop structure, especially for nested loops 2016-03-29 04:08:57 +00:00
ForwardSwitchConditionToPHI.ll
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HoistCode.ll
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InfLoop.ll [SimplifyCFG] Fix for "endless" loop after dead code removal (Alternative to 2016-02-03 23:54:25 +00:00
MagicPointer.ll [opaque pointer type] Add textual IR support for explicit type parameter to gep operator 2015-03-13 18:20:45 +00:00
PHINode.ll
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PR9946.ll
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PR16069.ll regenerate checks 2016-03-28 22:12:21 +00:00
PR17073.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
PR25267.ll [SimplifyCFG] Don't use-after-free an SSA value 2015-10-21 18:22:24 +00:00
PR27615-simplify-cond-br.ll [SimplifyCFG] isSafeToSpeculateStore now ignores debug info 2016-05-04 15:40:57 +00:00
PR29163.ll [SimplifyCFG] Hoisting invalidates metadata 2016-08-29 17:14:08 +00:00
PhiBlockMerge.ll regenerate checks 2016-03-28 22:12:21 +00:00
PhiBlockMerge2.ll
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PhiEliminate.ll
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PhiEliminate2.ll propagate 'unpredictable' metadata on select instructions 2016-03-17 15:30:52 +00:00
PhiEliminate3.ll
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PhiNoEliminate.ll
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SpeculativeExec.ll Revert "Revert "Strip metadata when speculatively hoisting instructions (r252604)" 2015-11-18 14:50:18 +00:00
UncondBranchToReturn.ll
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UnreachableEliminate.ll [SimplifyCFG] Replace calls to null/undef with unreachable 2016-06-25 07:37:27 +00:00
assume.ll
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attr-convergent.ll [SimplifyCFG] Don't fold conditional branches that contain calls to convergent functions. 2016-02-12 21:01:36 +00:00
attr-noduplicate.ll [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction 2015-02-27 19:29:02 +00:00
basictest.ll [SimplifyCFG] Prefer a simplification based on a dominating condition. 2016-05-06 14:25:14 +00:00
branch-cond-merge.ll
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branch-cond-prop.ll
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branch-fold-dbg.ll [PR27284] Reverse the ownership between DICompileUnit and DISubprogram. 2016-04-15 15:57:41 +00:00
branch-fold-test.ll
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branch-fold-threshold.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
branch-fold.ll
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branch-phi-thread.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
bug-25299.ll [SimplifyCFG] Extend SimplifyResume to handle phi of trivial landing pad. 2016-01-10 05:48:01 +00:00
clamp.ll [SimplifyCFG] Add test for r229099 2015-02-13 11:08:40 +00:00
combine-parallel-mem-md.ll [SimplifyCFG] Preserve !llvm.mem.parallel_loop_access when merging 2016-04-26 02:06:06 +00:00
common-dest-folding.ll [opaque pointer type] Add textual IR support for explicit type parameter to the call instruction 2015-04-16 23:24:18 +00:00
dbginfo.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
dce-cond-after-folding-terminator.ll
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duplicate-landingpad.ll Move the personality function from LandingPadInst to Function 2015-06-17 20:52:32 +00:00
duplicate-phis.ll
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empty-catchpad.ll [WinEH] Simplify unreachable catchpads 2016-01-05 02:37:41 +00:00
empty-cleanuppad.ll [SimplifyCFG] Don't kill empty cleanuppads with multiple uses 2016-06-04 23:50:03 +00:00
extract-cost.ll
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guards.ll [SimplifyCFG] Fold `llvm.guard(false)` to unreachable 2016-04-21 05:09:12 +00:00
hoist-common-code.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
hoist-dbgvalue.ll [PR27284] Reverse the ownership between DICompileUnit and DISubprogram. 2016-04-15 15:57:41 +00:00
hoist-with-range.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
implied-cond-matching-false-dest.ll [ValueTracking] Improve isImpliedCondition when the dominating cond is false. 2016-04-25 17:23:36 +00:00
implied-cond-matching-imm.ll [ValueTracking] Improve isImpliedCondition for matching LHS and Imm RHSs. 2016-05-05 15:39:18 +00:00
implied-cond-matching.ll Fix typo from r267432. 2016-04-25 18:20:27 +00:00
implied-cond.ll [SimplifyCFG] Constant fold a branch implied by it's incoming edge 2015-10-29 03:11:49 +00:00
indirectbr.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
invoke.ll Revert "[SimplifyCFG] Stop inserting calls to llvm.trap for UB" 2016-06-25 08:19:55 +00:00
invoke_unwind.ll [SimplifyCFG] Extend SimplifyResume to handle phi of trivial landing pad. 2016-01-10 05:48:01 +00:00
iterative-simplify.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
lifetime.ll Revert "[SimplifyCFG] Extend TryToSimplifyUncondBranchFromEmptyBlock for empty block including lifetime intrinsics" 2016-05-02 19:43:22 +00:00
merge-cleanuppads.ll [SimplifyCFG] Merge together cleanuppads 2016-02-20 01:07:45 +00:00
merge-cond-stores-2.ll Tweak unnamed label syntax in textual IR for easier matching in tests. 2016-01-27 21:53:08 +00:00
merge-cond-stores.ll Revert "Don't create unnecessary PHIs" 2015-12-14 22:36:57 +00:00
multiple-phis.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
no_speculative_loads_with_asan.ll [asan] Disabling speculative loads under asan. Patch by Mike Aizatsky 2015-10-14 00:21:05 +00:00
no_speculative_loads_with_tsan.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
noreturn-call.ll
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phi-undef-loadstore.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
preserve-branchweights-partial.ll IR: Make metadata typeless in assembly 2014-12-15 19:07:53 +00:00
preserve-branchweights-switch-create.ll IR: Make metadata typeless in assembly 2014-12-15 19:07:53 +00:00
preserve-branchweights.ll Follow-up patch of http://reviews.llvm.org/D19948 to handle missing profiles when simplifying CFG. 2016-05-18 22:41:03 +00:00
preserve-load-metadata-2.ll Preserve load alignment and dereferenceable metadata during some transformations 2015-11-02 17:53:51 +00:00
preserve-load-metadata-3.ll Preserve load alignment and dereferenceable metadata during some transformations 2015-11-02 17:53:51 +00:00
preserve-load-metadata.ll Preserve load alignment and dereferenceable metadata during some transformations 2015-11-02 17:53:51 +00:00
preserve-make-implicit-on-switch-to-br.ll [ConstantFoldTerminator] Preserve make.implicit metadata when converting SwitchInst to BranchInst 2015-08-07 19:30:12 +00:00
rangereduce.ll Actually, r277337 was fine. Just kill the DAGs that made the test allow nondeterminism. 2016-08-05 14:58:34 +00:00
return-merge.ll
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seh-nounwind.ll Move the personality function from LandingPadInst to Function 2015-06-17 20:52:32 +00:00
select-gep.ll [opaque pointer type] Add textual IR support for explicit type parameter to getelementptr instruction 2015-02-27 19:29:02 +00:00
sink-common-code.ll [SimplifyCFG] Handle tail-sinking of more than 2 incoming branches 2016-09-01 12:58:13 +00:00
speculate-math.ll Revert "Revert "[SimplifyCFG] allow speculation of exactly one expensive instruction (PR24818)"" 2016-01-27 02:59:41 +00:00
speculate-store.ll [SimplifyCFG] propagate branch metadata when creating select (PR26636) 2016-03-26 23:30:50 +00:00
speculate-vector-ops.ll
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speculate-with-offset.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
statepoint-invoke-unwind.ll [gc.statepoint] Change gc.statepoint intrinsic's return type to token type instead of i32 type 2015-12-26 07:54:32 +00:00
switch-dead-default.ll [SimplifyCFG] Use known bits to eliminate dead switch defaults 2015-09-10 17:44:47 +00:00
switch-masked-bits.ll [SimplifyCFG] eliminate switch cases based on known range of switch condition 2016-05-20 14:53:09 +00:00
switch-on-const-select.ll
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switch-range-to-icmp.ll SimplifyCFG: don't remove unreachable default switch destinations 2015-01-26 19:52:32 +00:00
switch-simplify-crash.ll
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switch-to-br.ll Add some tests for SimplifyCFG's ConstantFoldTerminator(). NFC. 2014-12-04 22:19:25 +00:00
switch-to-icmp.ll
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switch-to-select-multiple-edge-per-block-phi.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
switch-to-select-two-case.ll SimplifyCFG: don't remove unreachable default switch destinations 2015-01-26 19:52:32 +00:00
switch_create.ll Teaching SimplifyCFG to recognize the Or-Mask trick that InstCombine uses to 2016-06-24 01:59:00 +00:00
switch_switch_fold.ll use FileCheck for tighter checking 2016-03-16 23:39:37 +00:00
switch_thread.ll reduce check strings; no need to check IR comments 2016-03-16 23:22:01 +00:00
trap-debugloc.ll Revert "[SimplifyCFG] Stop inserting calls to llvm.trap for UB" 2016-06-25 08:19:55 +00:00
trapping-load-unreachable.ll Revert "[SimplifyCFG] Stop inserting calls to llvm.trap for UB" 2016-06-25 08:19:55 +00:00
two-entry-phi-return.ll [SimplifyCFG] propagate branch metadata when creating select (PR27344) 2016-04-15 15:32:12 +00:00
unreachable-blocks.ll [opaque pointer type] Add textual IR support for explicit type parameter to load instruction 2015-02-27 21:17:42 +00:00
unreachable-cleanuppad.ll [SimplifyCFG] Do not blindly remove unreachable blocks 2016-02-24 10:02:16 +00:00
volatile-phioper.ll [opaque pointer type] Add textual IR support for explicit type parameter to the call instruction 2015-04-16 23:24:18 +00:00
wineh-unreachable.ll [SimplifyCFG] Further improve our ability to remove redundant catchpads 2016-01-05 07:42:17 +00:00