llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-10-06 14:57:41 +00:00

History

Dan Gohman 9f93d30a26 ScalarEvolution support for <= and >= loops. Also, generalize ScalarEvolutions's min and max recognition to handle some new forms of min and max that this change makes more common. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@102234 91177308-0d34-0410-b5e6-96231b3b80d8		2010-04-24 03:09:42 +00:00
..
IPA	fix callgraph dump to not print 0x0x1234 for nodes.	2010-04-23 18:23:40 +00:00
AliasAnalysis.cpp
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp
BasicAliasAnalysis.cpp	Revert 101465, it broke internal OpenGL testing.	2010-04-16 23:37:20 +00:00
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt
ConstantFolding.cpp	Revert 101465, it broke internal OpenGL testing.	2010-04-16 23:37:20 +00:00
DbgInfoPrinter.cpp
DebugInfo.cpp
DomPrinter.cpp
InlineCost.cpp	Revert r101471. For tight recursive functions which have multiple	2010-04-21 00:43:30 +00:00
InstCount.cpp
InstructionSimplify.cpp	move some select simplifications out out instcombine into	2010-04-20 05:32:14 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	Remove the Expr member from IVUsers. Instead of remembering the expression,	2010-04-19 21:48:58 +00:00
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp	Tidy a comment.	2010-04-22 01:30:05 +00:00
LiveValues.cpp
LoopDependenceAnalysis.cpp
LoopInfo.cpp
LoopPass.cpp
Makefile
MemoryBuiltins.cpp	Revert 101465, it broke internal OpenGL testing.	2010-04-16 23:37:20 +00:00
MemoryDependenceAnalysis.cpp	Revert 101465, it broke internal OpenGL testing.	2010-04-16 23:37:20 +00:00
PHITransAddr.cpp
PointerTracking.cpp
PostDominators.cpp
ProfileEstimatorPass.cpp
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt	Fix LSR to tolerate cases where ScalarEvolution initially	2010-04-23 01:55:05 +00:00
ScalarEvolution.cpp	ScalarEvolution support for <= and >= loops.	2010-04-24 03:09:42 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp
Trace.cpp
ValueTracking.cpp	Revert 101465, it broke internal OpenGL testing.	2010-04-16 23:37:20 +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 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))

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