llvm-6502/lib/Analysis
Hal Finkel a739834446 Allow isDereferenceablePointer to look through some bitcasts
isDereferenceablePointer should not give up upon encountering any bitcast. If
we're casting from a pointer to a larger type to a pointer to a small type, we
can continue by examining the bitcast's operand. This missing capability
was noted in a comment in the function.

In order for this to work, isDereferenceablePointer now takes an optional
DataLayout pointer (essentially all callers already had such a pointer
available). Most code uses isDereferenceablePointer though
isSafeToSpeculativelyExecute (which already took an optional DataLayout
pointer), and to enable the LICM test case, LICM needs to actually provide its DL
pointer to isSafeToSpeculativelyExecute (which it was not doing previously).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212686 91177308-0d34-0410-b5e6-96231b3b80d8
2014-07-10 05:27:53 +00:00
..
IPA Add new lines to debugging information. 2014-07-03 02:11:49 +00:00
AliasAnalysis.cpp Improve BasicAA CS-CS queries 2014-07-08 23:16:49 +00:00
AliasAnalysisCounter.cpp [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr. 2014-04-15 04:59:12 +00:00
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr. 2014-04-15 04:59:12 +00:00
Analysis.cpp Revert "Introduce a string_ostream string builder facilty" 2014-06-26 22:52:05 +00:00
BasicAliasAnalysis.cpp Improve BasicAA CS-CS queries 2014-07-08 23:16:49 +00:00
BlockFrequencyInfo.cpp Revert "Introduce a string_ostream string builder facilty" 2014-06-26 22:52:05 +00:00
BlockFrequencyInfoImpl.cpp Support: Move class ScaledNumber 2014-06-24 00:38:09 +00:00
BranchProbabilityInfo.cpp [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE 2014-04-22 02:48:03 +00:00
CaptureTracking.cpp
CFG.cpp [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr. 2014-04-15 04:59:12 +00:00
CFGPrinter.cpp Clean up language and grammar. 2014-05-20 17:11:11 +00:00
CGSCCPassManager.cpp [PM] Add a new-PM-style CGSCC pass manager using the newly added 2014-04-21 11:12:00 +00:00
CMakeLists.txt Add a new attribute called 'jumptable' that creates jump-instruction tables for functions marked with this attribute. 2014-06-05 19:29:43 +00:00
CodeMetrics.cpp
ConstantFolding.cpp Remove old fenv.h workaround for a historic clang driver bug 2014-06-09 19:00:52 +00:00
CostModel.cpp [CostModel][x86] Improved cost model for alternate shuffles. 2014-07-03 22:24:18 +00:00
Delinearization.cpp remove BasePointer before delinearizing 2014-05-27 22:41:51 +00:00
DependenceAnalysis.cpp remove BasePointer before delinearizing 2014-05-27 22:41:51 +00:00
DominanceFrontier.cpp [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr. 2014-04-15 04:59:12 +00:00
DomPrinter.cpp
InstCount.cpp [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE 2014-04-22 02:48:03 +00:00
InstructionSimplify.cpp InstSimplify: Fix a bug when INT_MIN is in a sdiv 2014-07-04 00:23:39 +00:00
Interval.cpp
IntervalPartition.cpp [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr. 2014-04-15 04:59:12 +00:00
IVUsers.cpp Add back functionality removed in r210497. 2014-06-21 02:43:02 +00:00
JumpInstrTableInfo.cpp Add a new attribute called 'jumptable' that creates jump-instruction tables for functions marked with this attribute. 2014-06-05 19:29:43 +00:00
LazyCallGraph.cpp Fix typos 2014-05-15 01:52:21 +00:00
LazyValueInfo.cpp [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE 2014-04-22 02:48:03 +00:00
LibCallAliasAnalysis.cpp [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr. 2014-04-15 04:59:12 +00:00
LibCallSemantics.cpp [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr. 2014-04-15 04:59:12 +00:00
Lint.cpp Revert "Introduce a string_ostream string builder facilty" 2014-06-26 22:52:05 +00:00
LLVMBuild.txt
Loads.cpp [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr. 2014-04-15 04:59:12 +00:00
LoopInfo.cpp [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr. 2014-04-15 04:59:12 +00:00
LoopPass.cpp Add back functionality removed in r210497. 2014-06-21 02:43:02 +00:00
Makefile
MemDepPrinter.cpp [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr. 2014-04-15 04:59:12 +00:00
MemoryBuiltins.cpp [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE 2014-04-22 02:48:03 +00:00
MemoryDependenceAnalysis.cpp [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE 2014-04-22 02:48:03 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp Improve BasicAA CS-CS queries 2014-07-08 23:16:49 +00:00
PHITransAddr.cpp [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr. 2014-04-15 04:59:12 +00:00
PostDominators.cpp [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE 2014-04-22 02:48:03 +00:00
PtrUseVisitor.cpp
README.txt
RegionInfo.cpp [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE 2014-04-22 02:48:03 +00:00
RegionPass.cpp Add back functionality removed in r210497. 2014-06-21 02:43:02 +00:00
RegionPrinter.cpp Use unique_ptr to manage ownership of child Regions within llvm::Region 2014-04-15 18:32:43 +00:00
ScalarEvolution.cpp ScalarEvolution: Derive element size from the type of the loaded element 2014-06-08 19:21:20 +00:00
ScalarEvolutionAliasAnalysis.cpp [C++11] More 'nullptr' conversion. In some cases just using a boolean check instead of comparing to nullptr. 2014-04-15 04:59:12 +00:00
ScalarEvolutionExpander.cpp SCEVExpander: Fold constant PHIs harder. The logic below only understands proper IVs. 2014-06-21 11:47:18 +00:00
ScalarEvolutionNormalization.cpp test check-in: added missing parenthesis in comment 2014-05-28 19:03:33 +00:00
SparsePropagation.cpp [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE 2014-04-22 02:48:03 +00:00
TargetTransformInfo.cpp [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE 2014-04-22 02:48:03 +00:00
Trace.cpp
TypeBasedAliasAnalysis.cpp [TBAA] Fix handling of mixed TBAA (path-aware and non-path-aware TBAA). 2014-05-03 22:32:52 +00:00
ValueTracking.cpp Allow isDereferenceablePointer to look through some bitcasts 2014-07-10 05:27:53 +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))

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