llvm-6502/lib/Analysis
Duncan Sands d3a38ccfbb Fix a theoretical problem (not seen in the wild): if different instances of a
weak variable are compiled by different compilers, such as GCC and LLVM, while
LLVM may increase the alignment to the preferred alignment there is no reason to
think that GCC will use anything more than the ABI alignment.  Since it is the
GCC version that might end up in the final program (as the linkage is weak), it
is wrong to increase the alignment of loads from the global up to the preferred
alignment as the alignment might only be the ABI alignment.

Increasing alignment up to the ABI alignment might be OK, but I'm not totally
convinced that it is.  It seems better to just leave the alignment of weak
globals alone.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@145413 91177308-0d34-0410-b5e6-96231b3b80d8
2011-11-29 18:26:38 +00:00
..
IPA build: Add initial cut at LLVMBuild.txt files. 2011-11-03 18:53:17 +00:00
AliasAnalysis.cpp Enhance alias analysis for atomic instructions a bit. Upgrade a couple alias-analysis tests to the new atomic instructions. 2011-09-26 20:15:28 +00:00
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp land David Blaikie's patch to de-constify Type, with a few tweaks. 2011-07-18 04:54:35 +00:00
AliasDebugger.cpp
AliasSetTracker.cpp Atomic load/store support in LICM. 2011-08-15 20:52:09 +00:00
Analysis.cpp C API functions must be able to see their extern "C" definitions, or it will be impossible to call them from C. 2011-08-19 01:36:54 +00:00
BasicAliasAnalysis.cpp Refactor code to use new attribute getters on CallSite for NoCapture and ByVal. 2011-11-20 19:09:04 +00:00
BlockFrequencyInfo.cpp Add pass printing support to BlockFrequencyInfo pass. The implementation 2011-10-19 10:12:41 +00:00
BranchProbabilityInfo.cpp Remove all remaining uses of Value::getNameStr(). 2011-11-15 16:27:03 +00:00
CaptureTracking.cpp Fix crasher in GVN due to my recent capture tracking changes. 2011-11-21 19:42:56 +00:00
CFGPrinter.cpp Remove all remaining uses of Value::getNameStr(). 2011-11-15 16:27:03 +00:00
CMakeLists.txt Rewrite the CMake build to use explicit dependencies between libraries, 2011-07-29 00:14:25 +00:00
ConstantFolding.cpp Fixes following the CR by Chris and Duncan: 2011-08-29 19:58:36 +00:00
DbgInfoPrinter.cpp Fix for DbgInfoPrinter.cpp:174:12: warning: ‘LineNo’ may be used uninitialized in this function. 2011-09-21 23:34:23 +00:00
DebugInfo.cpp Update DebugInfoFinder to match recent debug info encoding changes. 2011-10-17 22:30:34 +00:00
DIBuilder.cpp Fix typo in comment. 2011-11-09 22:45:04 +00:00
DominanceFrontier.cpp Move DominanceFrontier from VMCore to Analysis. 2011-01-18 06:06:27 +00:00
DomPrinter.cpp
InlineCost.cpp A FIXME about block addresses and indirectbr. 2011-10-20 04:05:33 +00:00
InstCount.cpp
InstructionSimplify.cpp Fix code to match comment. Fixes PR11340, a regression from r143209. 2011-11-08 21:08:02 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp Slightly more useful tracing. 2011-10-13 17:06:38 +00:00
LazyValueInfo.cpp land David Blaikie's patch to de-constify Type, with a few tweaks. 2011-07-18 04:54:35 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp land David Blaikie's patch to de-constify Type, with a few tweaks. 2011-07-18 04:54:35 +00:00
LLVMBuild.txt build: Add initial cut at LLVMBuild.txt files. 2011-11-03 18:53:17 +00:00
Loads.cpp Add some comments here because the lack of a check for volatile/atomic here is a bit unusual. 2011-08-15 21:56:39 +00:00
LoopDependenceAnalysis.cpp Misc analysis passes that need to be aware of atomic load/store. 2011-08-15 20:54:19 +00:00
LoopInfo.cpp Remove the temporary flag -disable-unroll-scev and dead code. 2011-11-28 19:22:09 +00:00
LoopPass.cpp Reapply r138695. Fix PassManager stack depths. 2011-08-29 17:07:00 +00:00
Makefile
MemDepPrinter.cpp Enhance the memdep interface so that users can tell the difference between a dependency which cannot be calculated and a path reaching the entry point of the function. This patch introduces isNonFuncLocal, which replaces isUnknown in some cases. 2011-10-13 22:14:57 +00:00
MemoryBuiltins.cpp Validate the return type when checking if a function is malloc. 2011-11-23 17:58:47 +00:00
MemoryDependenceAnalysis.cpp Fix crasher in GVN due to my recent capture tracking changes. 2011-11-21 19:42:56 +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 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 Implementation of path profiling. 2011-01-29 01:09:53 +00:00
PathProfileVerifier.cpp Remove all remaining uses of Value::getNameStr(). 2011-11-15 16:27:03 +00:00
PHITransAddr.cpp Shorten some expressions by using ArrayRef::slice(). 2011-07-25 15:13:01 +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 Remove all remaining uses of Value::getNameStr(). 2011-11-15 16:27:03 +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 Remove all remaining uses of Value::getNameStr(). 2011-11-15 16:27:03 +00:00
ProfileVerifierPass.cpp Move code into anonymous namespaces. 2011-11-26 23:01:57 +00:00
README.txt
RegionInfo.cpp Missed some users of Value::getNameStr. 2011-11-15 18:30:06 +00:00
RegionPass.cpp Reapply r138695. Fix PassManager stack depths. 2011-08-29 17:07:00 +00:00
RegionPrinter.cpp RegionPrinter: Ignore back edges when layouting the graph 2011-02-27 04:11:07 +00:00
ScalarEvolution.cpp SCEV fix. In general, Add/Mul expressions should not inherit NSW/NUW. 2011-11-29 02:16:38 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp Fix SCEVExpander assert during LSR: "argument of incompatible type". 2011-10-15 06:19:55 +00:00
ScalarEvolutionNormalization.cpp Fix memory corruption I introduced a few checkins ago. 2011-10-13 18:49:23 +00:00
SparsePropagation.cpp Remove all remaining uses of Value::getNameStr(). 2011-11-15 16:27:03 +00:00
Trace.cpp Remove all remaining uses of Value::getNameStr(). 2011-11-15 16:27:03 +00:00
TypeBasedAliasAnalysis.cpp Fix a ton of comment typos found by codespell. Patch by 2011-04-15 05:18:47 +00:00
ValueTracking.cpp Fix a theoretical problem (not seen in the wild): if different instances of a 2011-11-29 18:26:38 +00:00

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))

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