llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-11-04 22:07:27 +00:00

History

Andrew Trick 5fd5b125ff Avoid creating canonical induction variables for non-native types. For example, on 32-bit architecture, don't promote all uses of the IV to 64-bits just because one use is a 64-bit cast. Alternate implementation of the patch by Arnaud de Grandmaison. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127884 91177308-0d34-0410-b5e6-96231b3b80d8		2011-03-18 16:50:32 +00:00
..
IPA
AliasAnalysis.cpp
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp	Delete the LiveValues pass. I won't get get back to the project it	2011-02-28 19:37:59 +00:00
BasicAliasAnalysis.cpp
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt	Unbreak CMake build.	2011-03-01 00:02:51 +00:00
ConstantFolding.cpp
DbgInfoPrinter.cpp	Move DbgInfoPrinter specific utlities inside DbgInfoPrinter.cpp	2011-02-15 17:36:11 +00:00
DebugInfo.cpp	Remove DIFactory. Patch by Devang.	2011-03-02 20:30:37 +00:00
DIBuilder.cpp	Today, the language front ends produces llvm.dbg.* intrinsics, used to encode arguments' debug info, in order any way, most of the times. However, if a front end mix-n-matches llvm.dbg.declare and llvm.dbg.value intrinsics to encode debug info for arguments then code generator needs a way to find argument order.	2011-03-01 22:58:13 +00:00
DominanceFrontier.cpp
DomPrinter.cpp
InlineCost.cpp
InstCount.cpp
InstructionSimplify.cpp	Fix two cases I forgot to update when doing a mental "getSwappedPredicate".	2011-03-09 08:20:06 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	Avoid creating canonical induction variables for non-native types.	2011-03-18 16:50:32 +00:00
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp
Loads.cpp
LoopDependenceAnalysis.cpp
LoopInfo.cpp
LoopPass.cpp	Introduce DebugInfoProbe. This is used to monitor how llvm optimizer is treating debugging information.	2011-03-10 00:21:25 +00:00
Makefile
MemDepPrinter.cpp
MemoryBuiltins.cpp	Add comments for the demanglings. Correct mangled form of operator delete!	2011-03-17 05:20:12 +00:00
MemoryDependenceAnalysis.cpp
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	RegionPrinter: Ignore back edges when layouting the graph	2011-02-27 04:11:07 +00:00
ScalarEvolution.cpp	Added isValidRewrite() to check the result of ScalarEvolutionExpander.	2011-03-17 23:51:11 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp	Added SCEV::NoWrapFlags to manage unsigned, signed, and self wrap	2011-03-14 16:50:06 +00:00
ScalarEvolutionNormalization.cpp	Added SCEV::NoWrapFlags to manage unsigned, signed, and self wrap	2011-03-14 16:50:06 +00:00
SparsePropagation.cpp
Trace.cpp
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp	Teach ComputeMaskedBits about sub nsw.	2011-03-12 17:18:11 +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))

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