llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-10-05 07:56:14 +00:00

History

Nick Lewycky d7ecff49d9 Don't try to loop on iterators that are potentially invalidated inside the loop. Fixes PR11361! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@144454 91177308-0d34-0410-b5e6-96231b3b80d8		2011-11-12 03:09:12 +00:00
..
IPA	build: Add initial cut at LLVMBuild.txt files.	2011-11-03 18:53:17 +00:00
AliasAnalysis.cpp
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp
BasicAliasAnalysis.cpp
BlockFrequencyInfo.cpp	Add pass printing support to BlockFrequencyInfo pass. The implementation	2011-10-19 10:12:41 +00:00
BranchProbabilityInfo.cpp	Fix the API usage in loop probability heuristics. It was incorrectly	2011-10-25 09:47:41 +00:00
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt
ConstantFolding.cpp
DbgInfoPrinter.cpp
DebugInfo.cpp	Update DebugInfoFinder to match recent debug info encoding changes.	2011-10-17 22:30:34 +00:00
DIBuilder.cpp	Fix typo in comment.	2011-11-09 22:45:04 +00:00
DominanceFrontier.cpp
DomPrinter.cpp
InlineCost.cpp	A FIXME about block addresses and indirectbr.	2011-10-20 04:05:33 +00:00
InstCount.cpp
InstructionSimplify.cpp	Fix code to match comment. Fixes PR11340, a regression from r143209.	2011-11-08 21:08:02 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	Slightly more useful tracing.	2011-10-13 17:06:38 +00:00
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp
LLVMBuild.txt	build: Add initial cut at LLVMBuild.txt files.	2011-11-03 18:53:17 +00:00
Loads.cpp
LoopDependenceAnalysis.cpp
LoopInfo.cpp
LoopPass.cpp
Makefile
MemDepPrinter.cpp	Enhance the memdep interface so that users can tell the difference between a dependency which cannot be calculated and a path reaching the entry point of the function. This patch introduces isNonFuncLocal, which replaces isUnknown in some cases.	2011-10-13 22:14:57 +00:00
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp	Enhance the memdep interface so that users can tell the difference between a dependency which cannot be calculated and a path reaching the entry point of the function. This patch introduces isNonFuncLocal, which replaces isUnknown in some cases.	2011-10-13 22:14:57 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
PathNumbering.cpp
PathProfileInfo.cpp
PathProfileVerifier.cpp
PHITransAddr.cpp
PostDominators.cpp
ProfileEstimatorPass.cpp
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt
RegionInfo.cpp
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp	Don't try to loop on iterators that are potentially invalidated inside the loop. Fixes PR11361!	2011-11-12 03:09:12 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp	Fix SCEVExpander assert during LSR: "argument of incompatible type".	2011-10-15 06:19:55 +00:00
ScalarEvolutionNormalization.cpp	Fix memory corruption I introduced a few checkins ago.	2011-10-13 18:49:23 +00:00
SparsePropagation.cpp
Trace.cpp
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp	A shift of a power of two is a power of two or zero.	2011-10-28 18:30:05 +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))

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