llvm-mirror

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History

Eli Friedman 884a7d08b1 When marking a block as being unanalyzable, use "Clobber" on the terminator instead of the first instruction in the block. This is a bit of a hack; "Clobber" isn't really the right marking in the first place. memdep doesn't really have any way of properly expressing "unanalyzable" at the moment. Using it on the terminator is much less ambiguous than using it on an arbitrary instruction, though. In the given testcase, the "Clobber" was pointing to a load, and GVN was incorrectly assuming that meant that the "Clobber" load overlapped the load being analyzed (when they are actually unrelated). The included testcase tests both this commit and r132434. Part two of rdar://9429882. (r132434 was mislabeled.) llvm-svn: 132442		2011-06-02 00:08:52 +00:00
..
IPA	Fix a source of non determinism in FindUsedTypes, use a SetVector instead of a	2011-05-13 05:20:42 +00:00
AliasAnalysis.cpp	When analyzing functions known to only access argument pointees,	2011-04-27 18:39:03 +00:00
AliasAnalysisCounter.cpp	Teach AliasAnalysisCounter about PartialAlias.	2010-12-10 19:53:05 +00:00
AliasAnalysisEvaluator.cpp	Teach AliasAnalysisEvaluator about PartialAlias.	2010-12-10 19:52:40 +00:00
AliasDebugger.cpp
AliasSetTracker.cpp	PR9604; try to deal with RAUW updates correctly in the AST. I'm not convinced	2011-04-09 06:55:46 +00:00
Analysis.cpp	remove postdom frontiers, because it is dead. Forward dom frontiers are	2011-04-05 21:57:17 +00:00
BasicAliasAnalysis.cpp	Make DecomposeGEPExpression check SimplifyInstruction only	2011-05-24 18:24:08 +00:00
CaptureTracking.cpp	Don't include Operator.h from InstrTypes.h.	2011-04-11 09:35:34 +00:00
CFGPrinter.cpp
CMakeLists.txt	Unbreak CMake build.	2011-03-01 00:02:51 +00:00
ConstantFolding.cpp	implement PR9315, constant folding exp2 in terms of pow (since hosts without	2011-05-22 22:22:35 +00:00
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	Use llvm.dbg.cu named metadata to collect compile units.	2011-05-03 16:18:28 +00:00
DominanceFrontier.cpp	Move DominanceFrontier from VMCore to Analysis.	2011-01-18 06:06:27 +00:00
DomPrinter.cpp	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
InlineCost.cpp	Change condition for determining whether a function is small for inlining metrics so that very long functions	2011-05-24 20:22:24 +00:00
InstCount.cpp
InstructionSimplify.cpp	The comparision "max(x,y)==x" is equivalent to "x>=y". Since the max is	2011-05-07 16:56:49 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	Update this comment.	2011-05-27 18:42:33 +00:00
LazyValueInfo.cpp	llvm.memcpy.* has two distinct associated address spaces; the source address space, and the destination address space. Fix up the interface on MemIntrinsic and MemTransferInst to make this clear, and fix InstructionDereferencesPointer in LazyValueInfo.cpp to use the interface properly.	2011-05-31 20:40:16 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp	PR9214: Convert ConstantExpr::getIndices() to return an ArrayRef, plus	2011-04-13 15:22:40 +00:00
Loads.cpp	Don't include Operator.h from InstrTypes.h.	2011-04-11 09:35:34 +00:00
LoopDependenceAnalysis.cpp	split dom frontier handling stuff out to its own DominanceFrontier header,	2011-01-02 22:09:33 +00:00
LoopInfo.cpp	Fix typo pointed out by Trevor Harmon.	2010-11-13 12:16:27 +00:00
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	Add helper functions for computing the Location of load, store,	2010-11-11 21:50:19 +00:00
MemoryBuiltins.cpp	Add comments for the demanglings. Correct mangled form of operator delete!	2011-03-17 05:20:12 +00:00
MemoryDependenceAnalysis.cpp	When marking a block as being unanalyzable, use "Clobber" on the terminator instead of the first instruction in the block. This is a bit of a hack; "Clobber" isn't really the right marking in the first place. memdep doesn't really have any way of properly expressing "unanalyzable" at the moment. Using it on the terminator is much less ambiguous than using it on an arbitrary instruction, though.	2011-06-02 00:08:52 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp	Use the new addEscapingValue callback to update GlobalsModRef when GVN adds PHIs of GEPs. For the moment,	2011-01-03 23:51:43 +00:00
PathNumbering.cpp	Remove unused STL header includes.	2011-04-23 19:53:52 +00:00
PathProfileInfo.cpp	Implementation of path profiling.	2011-01-29 01:09:53 +00:00
PathProfileVerifier.cpp	Fix a ton of comment typos found by codespell. Patch by	2011-04-15 05:18:47 +00:00
PHITransAddr.cpp	Don't include Operator.h from InstrTypes.h.	2011-04-11 09:35:34 +00:00
PostDominators.cpp	remove postdom frontiers, because it is dead. Forward dom frontiers are	2011-04-05 21:57:17 +00:00
ProfileEstimatorPass.cpp	Fix a ton of comment typos found by codespell. Patch by	2011-04-15 05:18:47 +00:00
ProfileInfo.cpp	Fix a ton of comment typos found by codespell. Patch by	2011-04-15 05:18:47 +00:00
ProfileInfoLoader.cpp	Remove unused STL header includes.	2011-04-23 19:53:52 +00:00
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt
RegionInfo.cpp	Region: Allow user control the printing style of the print function.	2011-04-04 07:19:18 +00:00
RegionPass.cpp	Minor change: Fix the typo in RegionPass.h and RegionPass.cpp.	2011-05-05 13:59:38 +00:00
RegionPrinter.cpp	RegionPrinter: Ignore back edges when layouting the graph	2011-02-27 04:11:07 +00:00
ScalarEvolution.cpp	SCEV: missing null check fix for r132360, dragonegg crash.	2011-06-01 19:14:56 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp	Remove PHINode::reserveOperandSpace(). Instead, add a parameter to	2011-03-30 11:28:46 +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	Fix a ton of comment typos found by codespell. Patch by	2011-04-15 05:18:47 +00:00
ValueTracking.cpp	Renamed llvm.x86.sse42.crc32 intrinsics; crc64 doesn't exist.	2011-05-26 23:13:19 +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))

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