llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-16 11:30:51 +00:00

History

Brendon Cahoon 8b94db17a4 Fix a type mismatch assert in SCEV division An assert was triggered when attempting to create a new SCEV with operands of different types in the visitAddRecExpr. In this test case, the operand types of the numerator and denominator are different. The SCEV division code should generate a conservative answer when this happens. Differential Revision: http://reviews.llvm.org/D9021 git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@235511 91177308-0d34-0410-b5e6-96231b3b80d8		2015-04-22 15:06:40 +00:00
..
IPA	[Inliner] Don't inline functions with frameescape calls	2015-04-14 20:38:14 +00:00
AliasAnalysis.cpp	Add new getModRefInfo API to determine whether an Instruction and a call modify the same memory	2015-04-13 23:25:41 +00:00
AliasAnalysisCounter.cpp	Use 'override/final' instead of 'virtual' for overridden methods	2015-04-11 02:11:45 +00:00
AliasAnalysisEvaluator.cpp	[CallSite] Make construction from Value* (or Instruction*) explicit.	2015-04-10 14:50:08 +00:00
AliasDebugger.cpp
AliasSetTracker.cpp	[CallSite] Make construction from Value* (or Instruction*) explicit.	2015-04-10 14:50:08 +00:00
Analysis.cpp	Divergence analysis for GPU programs	2015-04-10 05:03:50 +00:00
AssumptionCache.cpp
BasicAliasAnalysis.cpp
BlockFrequencyInfo.cpp
BlockFrequencyInfoImpl.cpp
BranchProbabilityInfo.cpp	Add range iterators for post order and inverse post order. Use them	2015-04-15 17:41:42 +00:00
CaptureTracking.cpp
CFG.cpp
CFGPrinter.cpp
CFLAliasAnalysis.cpp	Use 'override/final' instead of 'virtual' for overridden methods	2015-04-11 02:11:45 +00:00
CGSCCPassManager.cpp
CMakeLists.txt	Move IDF Calculation to a separate file, expose an interface to it.	2015-04-21 19:13:02 +00:00
CodeMetrics.cpp
ConstantFolding.cpp
CostModel.cpp
Delinearization.cpp
DependenceAnalysis.cpp
DivergenceAnalysis.cpp	Divergence analysis for GPU programs	2015-04-10 05:03:50 +00:00
DominanceFrontier.cpp
DomPrinter.cpp
InstCount.cpp
InstructionSimplify.cpp
Interval.cpp
IntervalPartition.cpp
IteratedDominanceFrontier.cpp	Move IDF Calculation to a separate file, expose an interface to it.	2015-04-21 19:13:02 +00:00
IVUsers.cpp
LazyCallGraph.cpp
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp
LLVMBuild.txt
Loads.cpp
LoopAccessAnalysis.cpp	[LoopAccesses] Improve debug output	2015-04-17 22:43:10 +00:00
LoopInfo.cpp
LoopPass.cpp
Makefile
MemDepPrinter.cpp	[CallSite] Make construction from Value* (or Instruction*) explicit.	2015-04-10 14:50:08 +00:00
MemDerefPrinter.cpp
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp	Revamp PredIteratorCache interface to be cleaner.	2015-04-21 21:11:50 +00:00
ModuleDebugInfoPrinter.cpp	DebugInfo: Drop rest of DIDescriptor subclasses	2015-04-21 18:44:06 +00:00
NoAliasAnalysis.cpp
PHITransAddr.cpp
PostDominators.cpp
PtrUseVisitor.cpp
README.txt
RegionInfo.cpp
RegionPass.cpp	Change range-based for-loops to be -Wrange-loop-analysis clean.	2015-04-15 01:21:15 +00:00
RegionPrinter.cpp	One more -Wrange-loop-analysis cleanup.	2015-04-15 21:40:50 +00:00
ScalarEvolution.cpp	Fix a type mismatch assert in SCEV division	2015-04-22 15:06:40 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp	[SCEV] Strengthen SCEVExpander::isHighCostExpansion.	2015-04-14 03:20:32 +00:00
ScalarEvolutionNormalization.cpp
ScopedNoAliasAA.cpp
SparsePropagation.cpp
StratifiedSets.h
TargetLibraryInfo.cpp
TargetTransformInfo.cpp	Divergence analysis for GPU programs	2015-04-10 05:03:50 +00:00
Trace.cpp
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp	[CallSite] Make construction from Value* (or Instruction*) explicit.	2015-04-10 14:50:08 +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))

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