llvm-6502

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History

Chandler Carruth 4147f39769 Temporarily revert r135528 which distinguishes between two copies of one inlined variable, based on the discussion in PR10542. This explodes the runtime of several passes down the pipeline due to a large number of "copies" remaining live across a large function. This only shows up with both debug and opt, but when it does it creates a many-minute compile when self-hosting LLVM+Clang. There are several other cases that show these types of regressions. All of this is tracked in PR10542, and progress is being made on fixing the issue. Once its addressed, the re-instated, but until then this restores the performance for self-hosting and other opt+debug builds. Devang, let me know if this causes any trouble, or impedes fixing it in any way, and thanks for working on this! git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136953 91177308-0d34-0410-b5e6-96231b3b80d8		2011-08-05 00:51:31 +00:00
..
IPA
AliasAnalysis.cpp
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp
BasicAliasAnalysis.cpp
BlockFrequencyInfo.cpp	Add more constantness in BlockFrequencyInfo.	2011-08-03 21:30:57 +00:00
BranchProbabilityInfo.cpp	Change SmallVector to SmallPtrSet in BranchProbabilityInfo. Handle cases where	2011-08-01 19:16:26 +00:00
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt
ConstantFolding.cpp
DbgInfoPrinter.cpp
DebugInfo.cpp	Temporarily revert r135528 which distinguishes between two copies of one	2011-08-05 00:51:31 +00:00
DIBuilder.cpp
DominanceFrontier.cpp
DomPrinter.cpp
InlineCost.cpp
InstCount.cpp
InstructionSimplify.cpp	Fix what seems an obvious typo. Patch by Ivan Krasin. Problem	2011-08-04 10:02:21 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp
Loads.cpp
LoopDependenceAnalysis.cpp
LoopInfo.cpp	Reverting r136884 updateUnloop, which crashed a linux builder.	2011-08-04 01:04:37 +00:00
LoopPass.cpp	Reverting r136884 updateUnloop, which crashed a linux builder.	2011-08-04 01:04:37 +00:00
Makefile
MemDepPrinter.cpp
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
PathNumbering.cpp	Add this back in for now. There are still a few passes which create unwind instructions at the moment.	2011-08-03 01:07:57 +00:00
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
ScalarEvolution.cpp	Use consistent terminology for loop exit/exiting blocks. Name change only.	2011-08-02 04:23:35 +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))

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