llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-11-03 14:08:57 +00:00

History

Andrew Trick d9fc1ce809 Fix 12513: Loop unrolling breaks with indirect branches. Take this opportunity to generalize the indirectbr bailout logic for loop transformations. CFG transformations will never get indirectbr right, and there's no point trying. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154386 91177308-0d34-0410-b5e6-96231b3b80d8		2012-04-10 05:14:42 +00:00
..
IPA	Handle intrinsics in GlobalsModRef. Fixes pr12351.	2012-03-28 21:31:24 +00:00
AliasAnalysis.cpp
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp
BasicAliasAnalysis.cpp
BlockFrequencyInfo.cpp
BranchProbabilityInfo.cpp
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt	Pull the implementation of the code metrics out of the inline cost	2012-03-16 05:51:52 +00:00
CodeMetrics.cpp	Initial commit for the rewrite of the inline cost analysis to operate	2012-03-31 12:42:41 +00:00
ConstantFolding.cpp
DbgInfoPrinter.cpp
DebugInfo.cpp	Add a line number for the scope of the function (starting at the first	2012-04-03 00:43:49 +00:00
DIBuilder.cpp	Add a line number for the scope of the function (starting at the first	2012-04-03 00:43:49 +00:00
DominanceFrontier.cpp
DomPrinter.cpp
InlineCost.cpp	Reintroduce InlineCostAnalyzer::getInlineCost() variant with explicit callee	2012-04-06 17:27:41 +00:00
InstCount.cpp
InstructionSimplify.cpp	Revert r153521 as it's causing large regressions on the nightly testers.	2012-03-28 18:42:50 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	Cleanup IVUsers::addUsersIfInteresting.	2012-03-22 17:47:33 +00:00
LazyValueInfo.cpp	llvm::SwitchInst	2012-03-11 06:09:17 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp	Always compute all the bits in ComputeMaskedBits.	2012-04-04 12:51:34 +00:00
LLVMBuild.txt
Loads.cpp	enhance jump threading to preserve TBAA information when PRE'ing loads,	2012-03-13 18:07:41 +00:00
LoopDependenceAnalysis.cpp
LoopInfo.cpp	Fix 12513: Loop unrolling breaks with indirect branches.	2012-04-10 05:14:42 +00:00
LoopPass.cpp	Take out the debug info probe stuff. It's making some changes to	2012-03-23 03:54:05 +00:00
Makefile
MemDepPrinter.cpp
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
PathNumbering.cpp
PathProfileInfo.cpp
PathProfileVerifier.cpp
PHITransAddr.cpp	Uniformize the InstructionSimplify interface by ensuring that all routines	2012-03-13 11:42:19 +00:00
PostDominators.cpp
ProfileEstimatorPass.cpp
ProfileInfo.cpp
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt
RegionInfo.cpp
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp	SCEV: When expanding a GEP the final addition to the base pointer has NUW but not NSW.	2012-04-07 17:19:26 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp
Trace.cpp
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp	Fix ValueTracking to conclude that debug intrinsics are safe to	2012-04-07 19:22:18 +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))

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