llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-07-23 01:30:19 +00:00

History

Duncan Sands 7c894691ef GCC doesn't understand that OrigAliasResult having a value is correlated with ArePhisAssumedNoAlias, and warns that OrigAliasResult may be used uninitialized. Pacify GCC. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@164229 91177308-0d34-0410-b5e6-96231b3b80d8		2012-09-19 15:43:44 +00:00
..
IPA	Release build: guard dump functions with	2012-09-12 05:06:18 +00:00
AliasAnalysis.cpp	Make MemoryBuiltins aware of TargetLibraryInfo.	2012-08-29 15:32:21 +00:00
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp	Release build: guard dump functions with	2012-09-12 05:06:18 +00:00
Analysis.cpp	Profile: set branch weight metadata with data generated from profiling.	2012-08-28 22:21:25 +00:00
BasicAliasAnalysis.cpp	GCC doesn't understand that OrigAliasResult having a value is correlated with	2012-09-19 15:43:44 +00:00
BlockFrequencyInfo.cpp
BranchProbabilityInfo.cpp	BranchProb: modify the definition of an edge in BranchProbabilityInfo to handle	2012-08-24 18:14:27 +00:00
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt	Profile: set branch weight metadata with data generated from profiling.	2012-08-28 22:21:25 +00:00
CodeMetrics.cpp
ConstantFolding.cpp	Dont cast away const needlessly. Found by gcc48 -Wcast-qual.	2012-09-06 15:42:13 +00:00
DbgInfoPrinter.cpp
DominanceFrontier.cpp	Release build: guard dump functions with	2012-09-12 05:06:18 +00:00
DomPrinter.cpp
InlineCost.cpp	Prevent inlining of callees which allocate lots of memory into a recursive caller.	2012-09-19 08:08:04 +00:00
InstCount.cpp
InstructionSimplify.cpp	Fix PR13412, a nasty miscompile due to the interleaved	2012-08-07 10:59:59 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	Release build: guard dump functions with	2012-09-12 05:06:18 +00:00
LazyValueInfo.cpp	JumpThreading: when default destination is the destination of some cases in a	2012-09-05 23:45:58 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp
LLVMBuild.txt
Loads.cpp
LoopDependenceAnalysis.cpp
LoopInfo.cpp	Release build: guard dump functions with	2012-09-12 05:06:18 +00:00
LoopPass.cpp
Makefile
MemDepPrinter.cpp
MemoryBuiltins.cpp	Make MemoryBuiltins aware of TargetLibraryInfo.	2012-08-29 15:32:21 +00:00
MemoryDependenceAnalysis.cpp	Be conservative about allocations that may alias the accessed pointer.	2012-09-04 03:30:13 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
PathNumbering.cpp
PathProfileInfo.cpp
PathProfileVerifier.cpp
PHITransAddr.cpp	Release build: guard dump functions with	2012-09-12 05:06:18 +00:00
PostDominators.cpp
ProfileDataLoader.cpp	Clean up ProfileDataLoader a bit.	2012-08-31 12:43:07 +00:00
ProfileDataLoaderPass.cpp	Cleanups due to feedback. No functionality change. Patch by Alistair.	2012-08-31 05:18:31 +00:00
ProfileEstimatorPass.cpp	Fix floating-point divide by zero, in a case where the value was not going to be used anyway.	2012-08-24 00:31:45 +00:00
ProfileInfo.cpp	Profile: set branch weight metadata with data generated from profiling.	2012-08-28 22:21:25 +00:00
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt
RegionInfo.cpp	Release build: guard dump functions with	2012-09-12 05:06:18 +00:00
RegionPass.cpp	Remove the the block_node_iterator of Region, replace it by the block_iterator.	2012-08-27 13:49:24 +00:00
RegionPrinter.cpp
ScalarEvolution.cpp	Release build: guard dump functions with	2012-09-12 05:06:18 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp	Fix a typo (the the => the)	2012-07-23 08:51:15 +00:00
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp
Trace.cpp	Release build: guard dump functions with	2012-09-12 05:06:18 +00:00
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp	Fix integer undefined behavior due to signed left shift overflow in LLVM.	2012-08-24 23:29:28 +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))

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