llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-11-02 07:11:49 +00:00

History

Duncan Sands d70d1a5c44 According to my auto-simplifier the most common missed simplifications in optimized code are: (non-negative number)+(power-of-two) != 0 -> true and (x \| 1) != 0 -> true Instcombine knows about the second one of course, but only does it if X\|1 has only one use. These fire thousands of times in the testsuite. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124183 91177308-0d34-0410-b5e6-96231b3b80d8		2011-01-25 09:38:29 +00:00
..
IPA	Use the new addEscapingValue callback to update GlobalsModRef when GVN adds PHIs of GEPs. For the moment,	2011-01-03 23:51:43 +00:00
AliasAnalysis.cpp	Stub out a new updating interface to AliasAnalysis, allowing stateful analyses to be informed when	2011-01-03 21:38:41 +00:00
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp	Move DominanceFrontier from VMCore to Analysis.	2011-01-18 06:06:27 +00:00
BasicAliasAnalysis.cpp	Give GetUnderlyingObject a TargetData, to keep it in sync	2011-01-24 18:53:32 +00:00
CaptureTracking.cpp	VAArg doesn't capture its operand.	2010-11-09 20:09:35 +00:00
CFGPrinter.cpp
CMakeLists.txt	Move DominanceFrontier from VMCore to Analysis.	2011-01-18 06:06:27 +00:00
ConstantFolding.cpp	Give GetUnderlyingObject a TargetData, to keep it in sync	2011-01-24 18:53:32 +00:00
DbgInfoPrinter.cpp
DebugInfo.cpp	Add support to create class type.	2010-12-08 20:18:20 +00:00
DIBuilder.cpp
DominanceFrontier.cpp	Move DominanceFrontier from VMCore to Analysis.	2011-01-18 06:06:27 +00:00
DomPrinter.cpp
InlineCost.cpp	Reorganize this so that the early exit and special cases come early	2011-01-25 01:34:31 +00:00
InstCount.cpp	Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which	2010-10-19 17:21:58 +00:00
InstructionSimplify.cpp	According to my auto-simplifier the most common missed simplifications in	2011-01-25 09:38:29 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
LazyValueInfo.cpp	Teach LazyValueInfo that allocas aren't NULL. Over all of llvm-test, this saves	2011-01-15 09:16:12 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp	Give GetUnderlyingObject a TargetData, to keep it in sync	2011-01-24 18:53:32 +00:00
LiveValues.cpp
Loads.cpp
LoopDependenceAnalysis.cpp	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
LoopInfo.cpp
LoopPass.cpp
Makefile	make -fno-rtti the default unless a directory builds with REQUIRES_RTTI.	2010-01-24 20:43:08 +00:00
MemDepPrinter.cpp
MemoryBuiltins.cpp	minor enhancement to llvm::isFreeCall API: return CallInst; no functional change	2010-06-23 21:51:12 +00:00
MemoryDependenceAnalysis.cpp	Give GetUnderlyingObject a TargetData, to keep it in sync	2011-01-24 18:53:32 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp	Use the new addEscapingValue callback to update GlobalsModRef when GVN adds PHIs of GEPs. For the moment,	2011-01-03 23:51:43 +00:00
PHITransAddr.cpp
PostDominators.cpp	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
ProfileEstimatorPass.cpp	fix PR8928 by clearing a stale map, patch by Jakub Staszak!	2011-01-24 18:36:51 +00:00
ProfileInfo.cpp	Null initialize a few variables flagged by	2011-01-23 17:05:06 +00:00
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt
RegionInfo.cpp	Add single entry / single exit accessors.	2011-01-13 23:18:04 +00:00
RegionPass.cpp	Remove useless dynamic_cast<>().	2010-12-12 21:58:28 +00:00
RegionPrinter.cpp	Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which	2010-10-19 17:21:58 +00:00
ScalarEvolution.cpp	Add a comment.	2011-01-24 17:54:18 +00:00
ScalarEvolutionAliasAnalysis.cpp	Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which	2010-10-19 17:21:58 +00:00
ScalarEvolutionExpander.cpp
ScalarEvolutionNormalization.cpp	Disable the asserts that check that normalization is perfectly	2010-09-03 22:12:56 +00:00
SparsePropagation.cpp
Trace.cpp
TypeBasedAliasAnalysis.cpp	Update a comment.	2010-12-16 02:55:10 +00:00
ValueTracking.cpp	According to my auto-simplifier the most common missed simplifications in	2011-01-25 09:38:29 +00:00

README.txt

Analysis Opportunities:

//===---------------------------------------------------------------------===//

In test/Transforms/LoopStrengthReduce/quadradic-exit-value.ll, the
ScalarEvolution expression for %r is this:

  {1,+,3,+,2}<loop>

Outside the loop, this could be evaluated simply as (%n * %n), however
ScalarEvolution currently evaluates it as

  (-2 + (2 * (trunc i65 (((zext i64 (-2 + %n) to i65) * (zext i64 (-1 + %n) to i65)) /u 2) to i64)) + (3 * %n))

In addition to being much more complicated, it involves i65 arithmetic,
which is very inefficient when expanded into code.

//===---------------------------------------------------------------------===//

In formatValue in test/CodeGen/X86/lsr-delayed-fold.ll,

ScalarEvolution is forming this expression:

((trunc i64 (-1 * %arg5) to i32) + (trunc i64 %arg5 to i32) + (-1 * (trunc i64 undef to i32)))

This could be folded to

(-1 * (trunc i64 undef to i32))

//===---------------------------------------------------------------------===//