llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-01-08 18:31:23 +00:00

History

Duncan Sands cf80bc1d4a Factorize common code out of the InstructionSimplify shift logic. Add in threading of shifts over selects and phis while there. This fires here and there in the testsuite, to not much effect. For example when compiling spirit it fires 5 times, during early-cse, resulting in 6 more cse simplifications, and 3 more terminators being folded by jump threading, but the final bitcode doesn't change in any interesting way: other optimizations would have caught the opportunity anyway, only later. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123441 91177308-0d34-0410-b5e6-96231b3b80d8		2011-01-14 14:44:12 +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	Teach AliasAnalysisCounter about PartialAlias.	2010-12-10 19:53:05 +00:00
AliasAnalysisEvaluator.cpp	Teach AliasAnalysisEvaluator about PartialAlias.	2010-12-10 19:52:40 +00:00
AliasDebugger.cpp	Extend the AliasAnalysis::pointsToConstantMemory interface to allow it	2010-11-08 16:45:26 +00:00
AliasSetTracker.cpp	Update this code to handle PartialAlias as MayAlias.	2010-12-10 19:40:47 +00:00
Analysis.cpp
BasicAliasAnalysis.cpp	fix rdar://8813415 - a miscompilation of 164.gzip that loop-idiom	2011-01-03 21:03:33 +00:00
CaptureTracking.cpp	VAArg doesn't capture its operand.	2010-11-09 20:09:35 +00:00
CFGPrinter.cpp	Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which	2010-10-19 17:21:58 +00:00
CMakeLists.txt
ConstantFolding.cpp	Teach constant folding to perform conversions from constant floating	2011-01-11 01:07:24 +00:00
DbgInfoPrinter.cpp
DebugInfo.cpp	Add support to create class type.	2010-12-08 20:18:20 +00:00
DIBuilder.cpp	Use type's file info while describing inheritance relationship.	2010-12-08 21:46:37 +00:00
DomPrinter.cpp	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
InlineCost.cpp
InstCount.cpp
InstructionSimplify.cpp	Factorize common code out of the InstructionSimplify shift logic. Add in	2011-01-14 14:44:12 +00:00
Interval.cpp
IntervalPartition.cpp	Now with fewer extraneous semicolons!	2010-10-07 22:25:06 +00:00
IVUsers.cpp	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
LazyValueInfo.cpp	Reorder, rename, and document some members to make this easier to follow.	2011-01-05 23:26:22 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp	Move Value::getUnderlyingObject to be a standalone	2010-12-15 20:02:24 +00:00
LiveValues.cpp	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
Loads.cpp	Move Value::getUnderlyingObject to be a standalone	2010-12-15 20:02:24 +00:00
LoopDependenceAnalysis.cpp	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
LoopInfo.cpp	Fix typo pointed out by Trevor Harmon.	2010-11-13 12:16:27 +00:00
LoopPass.cpp
Makefile
MemDepPrinter.cpp	Add helper functions for computing the Location of load, store,	2010-11-11 21:50:19 +00:00
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp	Revert r123207: "Turn on memdep's verifyRemoved() in an attempt to smoke out the cause of our gcc bootstrap miscompare."	2011-01-11 04:05:39 +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	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
PostDominators.cpp	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
ProfileEstimatorPass.cpp
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp	Get rid of static constructors for pass registration. Instead, every pass exposes an initializeMyPassFunction(), which	2010-10-19 17:21:58 +00:00
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
ScalarEvolution.cpp	some comment improvements.	2011-01-11 17:11:59 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp	Introduce memoization for ScalarEvolution dominates and properlyDominates	2010-11-18 00:34:22 +00:00
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp
Trace.cpp
TypeBasedAliasAnalysis.cpp	Update a comment.	2010-12-16 02:55:10 +00:00
ValueTracking.cpp	fix an off-by-one bug that caused a crash analyzing	2011-01-04 18:19:15 +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))

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