llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-01-01 00:33:09 +00:00

History

Nuno Lopes 41a3f25134 MemoryBuiltins: - recognize C++ new(std::nothrow) friends - ignore ExtractElement and ExtractValue instructions in size/offset analysis (all easy cases are probably folded away before we get here) - also recognize realloc as noalias git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@159356 91177308-0d34-0410-b5e6-96231b3b80d8		2012-06-28 16:34:03 +00:00
..
IPA	llvm/lib: [CMake] Add explicit dependency to intrinsics_gen.	2012-06-24 13:32:01 +00:00
AliasAnalysis.cpp
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp
BasicAliasAnalysis.cpp	refactor the MemoryBuiltin analysis:	2012-06-21 15:45:28 +00:00
BlockFrequencyInfo.cpp
BranchProbabilityInfo.cpp
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt	Fix cmake failure from moving files around.	2012-06-28 00:18:12 +00:00
CodeMetrics.cpp
ConstantFolding.cpp
DbgInfoPrinter.cpp	Move lib/Analysis/DebugInfo.cpp to lib/VMCore/DebugInfo.cpp and	2012-06-28 00:05:13 +00:00
DIBuilder.cpp	Move lib/Analysis/DebugInfo.cpp to lib/VMCore/DebugInfo.cpp and	2012-06-28 00:05:13 +00:00
DominanceFrontier.cpp
DomPrinter.cpp
InlineCost.cpp	Fix typos found by http://github.com/lyda/misspell-check	2012-06-02 10:20:22 +00:00
InstCount.cpp
InstructionSimplify.cpp
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp
LazyValueInfo.cpp	make LazyValueInfo analyze the default case of switch statements (we know that in the default branch the value cannot be any of the switch cases)	2012-06-28 16:13:37 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp
LLVMBuild.txt
Loads.cpp
LoopDependenceAnalysis.cpp
LoopInfo.cpp	Enable the new LoopInfo algorithm by default.	2012-06-26 04:11:38 +00:00
LoopPass.cpp	Enable the new LoopInfo algorithm by default.	2012-06-26 04:11:38 +00:00
Makefile
MemDepPrinter.cpp
MemoryBuiltins.cpp	MemoryBuiltins:	2012-06-28 16:34:03 +00:00
MemoryDependenceAnalysis.cpp	refactor the MemoryBuiltin analysis:	2012-06-21 15:45:28 +00:00
ModuleDebugInfoPrinter.cpp	Move lib/Analysis/DebugInfo.cpp to lib/VMCore/DebugInfo.cpp and	2012-06-28 00:05:13 +00:00
NoAliasAnalysis.cpp
PathNumbering.cpp
PathProfileInfo.cpp
PathProfileVerifier.cpp
PHITransAddr.cpp
PostDominators.cpp
ProfileEstimatorPass.cpp
ProfileInfo.cpp
ProfileInfoLoader.cpp	Round 2 of dead private variable removal.	2012-06-06 19:47:08 +00:00
ProfileInfoLoaderPass.cpp	Round 2 of dead private variable removal.	2012-06-06 19:47:08 +00:00
ProfileVerifierPass.cpp
README.txt
RegionInfo.cpp
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp	Fix typos found by http://github.com/lyda/misspell-check	2012-06-02 10:20:22 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp
Trace.cpp
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp

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))

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