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
..
BasicBlockUtils.cpp
BreakCriticalEdges.cpp
BuildLibCalls.cpp
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
CMakeLists.txt
CmpInstAnalysis.cpp
CodeExtractor.cpp
DemoteRegToStack.cpp
InlineFunction.cpp	Make sure the instruction right after an inlined function has a	2013-04-23 19:56:03 +00:00
InstructionNamer.cpp
IntegerDivision.cpp	Enhance integer division emulation support to handle types smaller than 32 bits,	2013-02-26 23:33:20 +00:00
LCSSA.cpp
LLVMBuild.txt
Local.cpp	fix a typo that due to cu&paste quadrupled itself	2013-04-26 18:10:50 +00:00
LoopSimplify.cpp
LoopUnroll.cpp
LoopUnrollRuntime.cpp
LowerExpectIntrinsic.cpp
LowerInvoke.cpp
LowerSwitch.cpp
Makefile
Mem2Reg.cpp
MetaRenamer.cpp
ModuleUtils.cpp
PromoteMemoryToRegister.cpp
SimplifyCFG.cpp	SimplifyCFG: If convert single conditional stores	2013-04-29 21:28:24 +00:00
SimplifyIndVar.cpp
SimplifyInstructions.cpp
SimplifyLibCalls.cpp	Do not optimise fprintf() calls if its return value is used.	2013-04-17 02:01:10 +00:00
SSAUpdater.cpp
UnifyFunctionExitNodes.cpp
Utils.cpp	Move C++ code out of the C headers and into either C++ headers	2013-04-22 22:47:22 +00:00
ValueMapper.cpp