llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-11-05 13:09:10 +00:00

History

Chandler Carruth e89ada98a6 Add some dead stores to pacify my least favorite GCC warning: may be uninitialized. The warning is terrible, has incorrect source locations, and has a huge false positive rate such as all of these. If anyone has a better solution, please let me know. Alternatively, I'll happily add -Wno-uninitialized to the -Werror build mode. Maybe I can even do it only when building with GCC instead of Clang. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120281 91177308-0d34-0410-b5e6-96231b3b80d8		2010-11-29 01:41:13 +00:00
..
IPA	Make ModRefBehavior a lattice. Use this to clean up AliasAnalysis	2010-11-10 01:02:18 +00:00
AliasAnalysis.cpp	add "getLocation" method to AliasAnalysis for getting the source and	2010-11-21 07:51:27 +00:00
AliasAnalysisCounter.cpp	Extend the AliasAnalysis::pointsToConstantMemory interface to allow it	2010-11-08 16:45:26 +00:00
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp	Extend the AliasAnalysis::pointsToConstantMemory interface to allow it	2010-11-08 16:45:26 +00:00
AliasSetTracker.cpp	Don't forget the TBAA info, if available.	2010-11-11 21:27:26 +00:00
Analysis.cpp
BasicAliasAnalysis.cpp	Make ModRefBehavior a lattice. Use this to clean up AliasAnalysis	2010-11-10 01:02:18 +00:00
CaptureTracking.cpp	VAArg doesn't capture its operand.	2010-11-09 20:09:35 +00:00
CFGPrinter.cpp
CMakeLists.txt	Introduce DIBuilder. It is intended to be a front-end friendly interface to emit debuggging information entries in LLVM IR.	2010-11-04 15:01:38 +00:00
ConstantFolding.cpp	Clarify that constant folding of instructions applies when all operands	2010-11-23 10:16:18 +00:00
DbgInfoPrinter.cpp
DebugInfo.cpp	Take care of special characters while creating named MDNode name to hold function specific local variable's info.	2010-11-10 22:19:21 +00:00
DIBuilder.cpp	Use arrays instead of constant-sized SmallVectors.	2010-11-04 18:45:27 +00:00
DomPrinter.cpp
InlineCost.cpp
InstCount.cpp
InstructionSimplify.cpp	Add some dead stores to pacify my least favorite GCC warning: may be	2010-11-29 01:41:13 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp	Now that hasConstantValue has been made simpler, it may return the	2010-11-17 10:23:23 +00:00
LiveValues.cpp
Loads.cpp
LoopDependenceAnalysis.cpp	Move SCEV::isLoopInvariant and hasComputableLoopEvolution to be member	2010-11-17 21:23:15 +00:00
LoopInfo.cpp	Fix typo pointed out by Trevor Harmon.	2010-11-13 12:16:27 +00:00
LoopPass.cpp
Makefile
MemDepPrinter.cpp	Add helper functions for computing the Location of load, store,	2010-11-11 21:50:19 +00:00
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp	Initialize MemDep's TD member so buildbots don't trip over an uninitialized pointer (TD is passed to PHITransAddr).	2010-11-21 15:21:46 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp	Extend the AliasAnalysis::pointsToConstantMemory interface to allow it	2010-11-08 16:45:26 +00:00
PHITransAddr.cpp	Strip trailing whitespace.	2010-11-18 17:06:31 +00:00
PostDominators.cpp
ProfileEstimatorPass.cpp
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt
RegionInfo.cpp
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp	Simplify code. No change in functionality.	2010-11-20 18:43:35 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp	Introduce memoization for ScalarEvolution dominates and properlyDominates	2010-11-18 00:34:22 +00:00
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp
Trace.cpp
TypeBasedAliasAnalysis.cpp	Re-disable TBAA for now; it broke MultiSource/Applications/JM/lencod,	2010-11-12 11:21:08 +00:00
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))

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