llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-15 04:30:12 +00:00

History

Chris Lattner d2bfe54b0a Fix PR7647, handling the case when 'To' ends up being mutated by recursive simplification. This also enhances ReplaceAndSimplifyAllUses to actually do a real RAUW at the end of it, which updates any value handles pointing to "From" to start pointing to "To". This seems useful for debug info and random other VH users. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108415 91177308-0d34-0410-b5e6-96231b3b80d8		2010-07-15 06:36:08 +00:00
..
IPA	cache result of operator*	2010-07-09 16:22:36 +00:00
AliasAnalysis.cpp	Remove interprocedural-basic-aa and associated code. The AliasAnalysis	2010-07-07 14:27:09 +00:00
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp	Remove interprocedural-basic-aa and associated code. The AliasAnalysis	2010-07-07 14:27:09 +00:00
AliasDebugger.cpp	Fix AliasDebugger to be aware of operand values too.	2010-05-28 22:31:51 +00:00
AliasSetTracker.cpp
Analysis.cpp
BasicAliasAnalysis.cpp	Minore code simplification.	2010-07-07 14:30:04 +00:00
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt	Move FindAvailableLoadedValue isSafeToLoadUnconditionally out of	2010-05-28 16:19:17 +00:00
ConstantFolding.cpp	Add parentheses around an \|\| to correct the logic. Also silences a GCC warning	2010-07-12 06:47:05 +00:00
DbgInfoPrinter.cpp
DebugInfo.cpp	Reverting r107918 and r107919. Radar 8063111.	2010-07-08 23:25:39 +00:00
DomPrinter.cpp	Convert some tab stops into spaces.	2010-07-12 08:16:59 +00:00
InlineCost.cpp	Pulled CodeMetrics out of InlineCost.h and made it a bit more general, so it can be reused from PartialSpecializationCost	2010-06-09 15:11:37 +00:00
InstCount.cpp
InstructionSimplify.cpp	Fix PR7647, handling the case when 'To' ends up being	2010-07-15 06:36:08 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	Remove the Expr member from IVUsers. Instead of remembering the expression,	2010-04-19 21:48:58 +00:00
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp	Add a lint check for mismatched return types, inspired by PR6944.	2010-07-12 18:02:04 +00:00
LiveValues.cpp
Loads.cpp	Move FindAvailableLoadedValue isSafeToLoadUnconditionally out of	2010-05-28 16:19:17 +00:00
LoopDependenceAnalysis.cpp
LoopInfo.cpp	cache result of operator*	2010-07-09 14:28:41 +00:00
LoopPass.cpp
Makefile
MemoryBuiltins.cpp	minor enhancement to llvm::isFreeCall API: return CallInst; no functional change	2010-06-23 21:51:12 +00:00
MemoryDependenceAnalysis.cpp	use the new isFreeCall API and ArgOperand accessors	2010-06-23 22:48:06 +00:00
ModuleDebugInfoPrinter.cpp	Add a simple module-level debug info printer. It just sets up a	2010-05-07 16:22:32 +00:00
PHITransAddr.cpp
PointerTracking.cpp	Rename isLoopGuardedByCond to isLoopEntryGuardedByCond, to emphasise	2010-04-11 19:27:13 +00:00
PostDominators.cpp	cache result of operator*	2010-07-09 15:52:36 +00:00
ProfileEstimatorPass.cpp
ProfileInfo.cpp	Remove a pointless variable.	2010-06-29 11:39:45 +00:00
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt	When checking whether the special handling for an addrec increment which	2010-04-26 21:46:36 +00:00
ScalarEvolution.cpp	In ScalarEvolution::forgetValue, eliminate any SCEVUnknown	2010-06-30 20:21:12 +00:00
ScalarEvolutionAliasAnalysis.cpp	Rework scev-aa's basic computation so that it doesn't depend	2010-06-30 06:12:16 +00:00
ScalarEvolutionExpander.cpp	remove useless cast and fix typos in comment	2010-07-09 16:42:04 +00:00
ScalarEvolutionNormalization.cpp	Fix normalization and de-normalization of non-affine SCEVs.	2010-06-04 19:16:34 +00:00
SparsePropagation.cpp
Trace.cpp
ValueTracking.cpp	use ArgOperand accessors	2010-06-23 23:38:07 +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))

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