llvm-6502/test/Transforms/SimplifyCFG
Arnold Schwaighofer 8228ffe72d 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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@180731 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-29 21:28:24 +00:00
..
SPARC Use TargetTransformInfo to control switch-to-lookup table transformation 2012-10-30 11:23:25 +00:00
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 Convert all tests using TCL-style quoting to use shell-style quoting. 2012-07-02 12:47:22 +00:00
2008-07-13-InfLoopMiscompile.ll Convert all tests using TCL-style quoting to use shell-style quoting. 2012-07-02 12:47:22 +00:00
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 Fix SpeculativelyExecuteBB to either speculate all or none of the phis 2012-01-05 23:58:56 +00:00
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 Remove dyn_cast + dereference pattern by replacing it with a cast and changing 2012-06-24 10:15:42 +00:00
branch-phi-thread.ll Fix the remaining TCL-style quotes found in the testsuite. This is 2012-07-02 19:09:46 +00:00
BrUnwind.ll Fix the remaining TCL-style quotes found in the testsuite. This is 2012-07-02 19:09:46 +00:00
dbginfo.ll
dce-cond-after-folding-terminator.ll
DeadSetCC.ll Fix the remaining TCL-style quotes found in the testsuite. This is 2012-07-02 19:09:46 +00:00
duplicate-phis.ll Convert all tests using TCL-style quoting to use shell-style quoting. 2012-07-02 12:47:22 +00:00
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 fix PR13339 (remove the predecessor from the unwind BB when removing an invoke) 2012-07-16 22:49:40 +00:00
iterative-simplify.ll
lifetime.ll
lit.local.cfg Replace all instances of dg.exp file with lit.local.cfg, since all tests are run with LIT now and now Dejagnu. dg.exp is no longer needed. 2012-02-16 06:28:33 +00:00
MagicPointer.ll
multiple-phis.ll Fix SpeculativelyExecuteBB to either speculate all or none of the phis 2012-01-05 23:58:56 +00:00
noreturn-call.ll
phi-undef-loadstore.ll SimplifyCFG: Enhance the "remove CFG edge that leads to null pointer dereference" optimization to also handle instructions with multiple uses. 2012-10-04 16:11:49 +00:00
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 Remove an incorrect assert during branch weight propagation. 2012-09-08 00:07:26 +00:00
preserve-branchweights-switch-create.ll PGO: preserve branch-weight metadata when merging two switches where 2012-09-14 17:29:56 +00:00
preserve-branchweights.ll PGO: preserve branch-weight metadata when simplifying Switch to a sub, an icmp 2012-09-18 00:47:33 +00:00
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 SimplifyCFG: sink common codes from IF, ELSE blocks down to END block. 2012-09-20 22:37:36 +00:00
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 Fix the remaining TCL-style quotes found in the testsuite. This is 2012-07-02 19:09:46 +00:00
switch-masked-bits.ll Fix SpeculativelyExecuteBB to either speculate all or none of the phis 2012-01-05 23:58:56 +00:00
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 Fix the remaining TCL-style quotes found in the testsuite. This is 2012-07-02 19:09:46 +00:00
unreachable-blocks.ll Make Value::isDereferenceablePointer() handle unreachable code blocks. (This 2012-01-23 00:05:17 +00:00
UnreachableEliminate.ll
volatile-phioper.ll SimplifyCFG fix for volatile load/store. 2013-03-07 01:03:35 +00:00