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
..
Hello	Move all of the header files which are involved in modelling the LLVM IR	2013-01-02 11:36:10 +00:00
InstCombine	Move C++ code out of the C headers and into either C++ headers	2013-04-22 22:47:22 +00:00
Instrumentation	Move C++ code out of the C headers and into either C++ headers	2013-04-22 22:47:22 +00:00
IPO	Move C++ code out of the C headers and into either C++ headers	2013-04-22 22:47:22 +00:00
ObjCARC	Add in some conditional compilation in order to silence an unused variable warning.	2013-04-29 07:29:08 +00:00
Scalar	Fix a XOR reassociation bug.	2013-04-27 18:02:12 +00:00
Utils	SimplifyCFG: If convert single conditional stores	2013-04-29 21:28:24 +00:00
Vectorize	LoopVectorizer: Calculate the number of pointers to disambiguate at runtime based on the numbers of reads and writes.	2013-04-26 05:08:59 +00:00
CMakeLists.txt	Extracted ObjCARC.cpp into its own library libLLVMObjCARCOpts in preparation for refactoring the ARC Optimizer.	2013-01-28 01:35:51 +00:00
LLVMBuild.txt	Extracted ObjCARC.cpp into its own library libLLVMObjCARCOpts in preparation for refactoring the ARC Optimizer.	2013-01-28 01:35:51 +00:00
Makefile	Extracted ObjCARC.cpp into its own library libLLVMObjCARCOpts in preparation for refactoring the ARC Optimizer.	2013-01-28 01:35:51 +00:00