llvm/lib/Transforms/Utils
Arnold Schwaighofer 54d9a3e2df Revert "SimplifyCFG: If convert single conditional stores"
There is the temptation to make this tranform dependent on target information as
it is not going to be beneficial on all (sub)targets. Therefore, we should
probably do this in MI Early-Ifconversion.

This reverts commit r179957. Original commit message:

"SimplifyCFG: If convert single conditional 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 were 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.

I am going to watch performance numbers across the builtbots and will revert
this if anything unexpected comes up."

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179980 91177308-0d34-0410-b5e6-96231b3b80d8
2013-04-21 13:09:04 +00:00
..
BasicBlockUtils.cpp Remove trailing spaces. 2013-01-14 23:16:36 +00:00
BreakCriticalEdges.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
BuildLibCalls.cpp Convert BuildLibCalls.cpp to using the AttributeSet methods instead of AttributeWithIndex. 2013-01-26 00:03:11 +00:00
BypassSlowDivision.cpp Bypass Slow Divides 2013-03-04 18:13:57 +00:00
CloneFunction.cpp Change CloneFunctionInto to always clone Argument attributes induvidually, 2013-04-10 10:37:38 +00:00
CloneModule.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
CMakeLists.txt Sink the AddressingModeMatcher helper class into an anonymous namespace 2013-01-05 02:09:22 +00:00
CmpInstAnalysis.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
CodeExtractor.cpp Remove #includes from the commonly used LoopInfo.h. 2013-02-09 01:04:28 +00:00
DemoteRegToStack.cpp [SjLj Prepare] When demoting an invoke instructions to the stack, if the normal 2013-02-05 18:23:10 +00:00
InlineFunction.cpp Add all clauses when merging the landing pads. Duplicates will be handled later on. 2013-03-22 20:31:05 +00:00
InstructionNamer.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
IntegerDivision.cpp Enhance integer division emulation support to handle types smaller than 32 bits, 2013-02-26 23:33:20 +00:00
LCSSA.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
LLVMBuild.txt LLVMBuild: Remove trailing newline, which irked me. 2011-12-12 19:48:00 +00:00
Local.cpp Fix llvm::removeUnreachableBlocks to handle unreachable loops. 2013-03-22 08:43:04 +00:00
LoopSimplify.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
LoopUnroll.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
LoopUnrollRuntime.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
LowerExpectIntrinsic.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
LowerInvoke.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
LowerSwitch.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
Makefile make -fno-rtti the default unless a directory builds with REQUIRES_RTTI. 2010-01-24 20:43:08 +00:00
Mem2Reg.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
MetaRenamer.cpp Make sure metarenamer won't rename special stuff (intrinsics and explicitly renamed stuff). 2013-01-23 15:03:08 +00:00
ModuleUtils.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
PromoteMemoryToRegister.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
SimplifyCFG.cpp Revert "SimplifyCFG: If convert single conditional stores" 2013-04-21 13:09:04 +00:00
SimplifyIndVar.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
SimplifyInstructions.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
SimplifyLibCalls.cpp Do not optimise fprintf() calls if its return value is used. 2013-04-17 02:01:10 +00:00
SSAUpdater.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
UnifyFunctionExitNodes.cpp Move all of the header files which are involved in modelling the LLVM IR 2013-01-02 11:36:10 +00:00
Utils.cpp Add a pass that renames everything with metasyntatic names. This works well after using bugpoint to reduce the confusion presented by the original names, which no longer mean what they used to. 2012-09-11 02:46:18 +00:00
ValueMapper.cpp Linker: correctly link in dbg.declare 2013-01-31 21:19:18 +00:00