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llvm-mirror/test/Transforms/SimplifyCFG
Arnold Schwaighofer d0c38e0586 SimplifyCFG: If convert single conditional stores
This resurrects r179957, but adds code that makes sure we don't touch
atomic/volatile stores:

This transformation will transform a conditional store with a preceeding
uncondtional store to the same location:

 a[i] =
 may-alias with a[i] load
 if (cond)
   a[i] = Y

into an unconditional store.

 a[i] = X
 may-alias with a[i] load
 tmp = cond ? Y : X;
 a[i] = tmp

We assume that on average the cost of a mispredicted branch is going to be
higher than the cost of a second store to the same location, and that the
secondary benefits of creating a bigger basic block for other optimizations to
work on outway the potential case where the branch would be correctly predicted
and the cost of the executing the second store would be noticably reflected in
performance.

hmmer's execution time improves by 30% on an imac12,2 on ref data sets. With
this change we are on par with gcc's performance (gcc also performs this
transformation). There was a 1.2 % performance improvement on a ARM swift chip.
Other tests in the test-suite+external seem to be mostly uninfluenced in my
experiments:
This optimization was triggered on 41 tests such that the executable was
different before/after the patch. Only 1 out of the 40 tests (dealII) was
reproducable below 100% (by about .4%). Given that hmmer benefits so much I
believe this to be a fair trade off.

llvm-svn: 180731
2013-04-29 21:28:24 +00:00
..
SPARC
X86 Fix logic to determine whether to turn a switch into a lookup table. When 2012-11-30 02:02:42 +00:00
2002-05-21-PHIElimination.ll
2002-09-24-PHIAssertion.ll
2003-03-07-DominateProblem.ll
2003-08-05-InvokeCrash.ll
2003-08-17-BranchFold.ll Converted 8x tests of SimplifyCFG to use FileCheck instead of grep. 2013-04-09 05:18:53 +00:00
2003-08-17-BranchFoldOrdering.ll Converted 8x tests of SimplifyCFG to use FileCheck instead of grep. 2013-04-09 05:18:53 +00:00
2003-08-17-FoldSwitch-dbg.ll Converted 8x tests of SimplifyCFG to use FileCheck instead of grep. 2013-04-09 05:18:53 +00:00
2003-08-17-FoldSwitch.ll Converted 8x tests of SimplifyCFG to use FileCheck instead of grep. 2013-04-09 05:18:53 +00:00
2004-12-10-SimplifyCFGCrash.ll
2005-06-16-PHICrash.ll
2005-08-01-PHIUpdateFail.ll
2005-10-02-InvokeSimplify.ll
2005-12-03-IncorrectPHIFold.ll Converted 8x tests of SimplifyCFG to use FileCheck instead of grep. 2013-04-09 05:18:53 +00:00
2006-02-17-InfiniteUnroll.ll
2006-06-12-InfLoop.ll
2006-08-03-Crash.ll
2006-10-19-UncondDiv.ll Converted 8x tests of SimplifyCFG to use FileCheck instead of grep. 2013-04-09 05:18:53 +00:00
2006-12-08-Ptr-ICmp-Branch.ll
2007-11-22-InvokeNoUnwind.ll Converted 8x tests of SimplifyCFG to use FileCheck instead of grep. 2013-04-09 05:18:53 +00:00
2007-12-21-Crash.ll
2008-01-02-hoist-fp-add.ll Converted 8x tests of SimplifyCFG to use FileCheck instead of grep. 2013-04-09 05:18:53 +00:00
2008-05-16-PHIBlockMerge.ll
2008-07-13-InfLoopMiscompile.ll
2008-09-08-MultiplePred.ll
2008-09-17-SpeculativeHoist.ll
2008-10-03-SpeculativelyExecuteBeforePHI.ll
2008-12-06-SingleEntryPhi.ll
2008-12-16-DCECond.ll
2009-01-18-PHIPropCrash.ll
2009-01-19-UnconditionalTrappingConstantExpr.ll
2009-05-12-externweak.ll
2010-03-30-InvokeCrash.ll Tests: rewrite 'opt ... %s' to 'opt ... < %s' so that opt does not emit a ModuleID 2013-01-01 13:57:25 +00:00
2011-03-08-UnreachableUse.ll
2011-09-05-TrivialLPad.ll
basictest.ll
branch-cond-merge.ll
branch-cond-prop.ll
branch-fold-dbg.ll Tests: rewrite 'opt ... %s' to 'opt ... < %s' so that opt does not emit a ModuleID 2012-12-30 01:28:40 +00:00
branch-fold-test.ll
branch-fold.ll
branch-phi-thread.ll
BrUnwind.ll
dbginfo.ll
dce-cond-after-folding-terminator.ll
DeadSetCC.ll
duplicate-phis.ll
EmptyBlockMerge.ll Filecheckized 2x tests in SimplifyCFG and removed their date prefix to fit with current llvm style for test names. 2013-01-31 01:04:23 +00:00
EqualPHIEdgeBlockMerge.ll
ForwardSwitchConditionToPHI.ll
hoist-common-code.ll
hoist-dbgvalue.ll
HoistCode.ll
indirectbr.ll
invoke_unwind.ll
invoke.ll
iterative-simplify.ll
lifetime.ll
lit.local.cfg
MagicPointer.ll
multiple-phis.ll
noreturn-call.ll
phi-undef-loadstore.ll
PhiBlockMerge2.ll
PhiBlockMerge.ll
PhiEliminate2.ll
PhiEliminate3.ll
PhiEliminate.ll
PHINode.ll Filecheckized 2x tests in SimplifyCFG and removed their date prefix to fit with current llvm style for test names. 2013-01-31 01:04:23 +00:00
PhiNoEliminate.ll
PR9946.ll Tests: rewrite 'opt ... %s' to 'opt ... < %s' so that opt does not emit a ModuleID 2013-01-01 13:57:25 +00:00
preserve-branchweights-partial.ll
preserve-branchweights-switch-create.ll
preserve-branchweights.ll
return-merge.ll
select-gep.ll Tests: rewrite 'opt ... %s' to 'opt ... < %s' so that opt does not emit a ModuleID 2012-12-30 01:28:40 +00:00
sink-common-code.ll
speculate-store.ll SimplifyCFG: If convert single conditional stores 2013-04-29 21:28:24 +00:00
speculate-with-offset.ll
SpeculativeExec.ll Re-revert r173342, without losing the compile time improvements, flat 2013-01-27 06:42:03 +00:00
switch_create.ll Only do switch-to-lookup table transformation when TargetTransformInfo 2012-11-07 21:35:12 +00:00
switch_switch_fold.ll
switch_thread.ll
switch-masked-bits.ll
switch-on-const-select.ll Use references to attribute groups on the call/invoke instructions. 2013-02-22 09:09:42 +00:00
switch-simplify-crash.ll
switch-to-icmp.ll simplifycfg: Fix integer overflow converting switch into icmp. 2013-04-16 08:35:36 +00:00
trap-debugloc.ll
trapping-load-unreachable.ll
trivial-throw.ll Don't remove a landing pad if the invoke requires a table entry. 2013-03-11 20:53:00 +00:00
two-entry-phi-return.ll
UncondBranchToReturn.ll
unreachable-blocks.ll
UnreachableEliminate.ll
volatile-phioper.ll SimplifyCFG fix for volatile load/store. 2013-03-07 01:03:35 +00:00