llvm-6502/lib/Analysis
Chandler Carruth 9156c5e3ba Teach the load analysis to allow finding available values which require
inttoptr or ptrtoint cast provided there is datalayout available.
Eventually, the datalayout can just be required but in practice it will
always be there today.

To go with the ability to expose available values requiring a ptrtoint
or inttoptr cast, helpers are added to perform one of these three casts.

These smarts are necessary to finish canonicalizing loads and stores to
the operational type requirements without regressing fundamental
combines.

I've added some test cases. These should actually improve as the load
combining and store combining improves, but they may fundamentally be
highlighting some missing combines for select in addition to exercising
the specific added logic to load analysis.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220277 91177308-0d34-0410-b5e6-96231b3b80d8
2014-10-21 09:00:40 +00:00
..
IPA Add functions for finding ephemeral values 2014-09-07 13:49:57 +00:00
AliasAnalysis.cpp Make AAMDNodes ctor and operator bool (!!!) explicit, mop up bugs and weirdness exposed by it. 2014-10-04 22:44:29 +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 AA metadata refactoring (introduce AAMDNodes) 2014-07-24 12:16:19 +00:00
AliasDebugger.cpp [C++11] Add 'override' keyword to virtual methods that override their base class. 2014-03-05 07:30:04 +00:00
AliasSetTracker.cpp AA metadata refactoring (introduce AAMDNodes) 2014-07-24 12:16:19 +00:00
Analysis.cpp Add a CFL Alias Analysis implementation 2014-09-02 21:43:13 +00:00
AssumptionTracker.cpp AssumptionTracker: Don't create temporary CallbackVHs. 2014-10-11 19:13:01 +00:00
BasicAliasAnalysis.cpp Revert "[BasicAA] Revert "Revert r218714 - Make better use of zext and sign information."" 2014-10-09 19:48:12 +00:00
BlockFrequencyInfo.cpp Revert "Introduce a string_ostream string builder facilty" 2014-06-26 22:52:05 +00:00
BlockFrequencyInfoImpl.cpp [modules] Stop excluding Support/Debug.h from the Support module. This header 2014-10-13 00:41:03 +00:00
BranchProbabilityInfo.cpp Revert "[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges." 2014-07-21 17:06:51 +00:00
CaptureTracking.cpp Match semantics of PointerMayBeCapturedBefore to its name by default 2014-07-21 21:30:22 +00:00
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 Modernize raw_fd_ostream's constructor a bit. 2014-08-25 18:16:47 +00:00
CFLAliasAnalysis.cpp [CFL-AA] CFL-AA should not assert on an va_arg instruction 2014-10-14 20:51:26 +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 file to CMake build as well. 2014-09-18 00:39:20 +00:00
CodeMetrics.cpp Treat the WorkSet used to find ephemeral values as double-ended 2014-10-15 17:34:48 +00:00
ConstantFolding.cpp Remove duplicate function names from comments. NFC. 2014-10-02 15:13:22 +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 Analysis: cleanup 2014-08-26 02:03:40 +00:00
DominanceFrontier.cpp Templatify DominanceFrontier. 2014-07-12 21:59:52 +00:00
DomPrinter.cpp [PM] Split DominatorTree into a concrete analysis result object which 2014-01-13 13:07:17 +00:00
FunctionTargetTransformInfo.cpp Add a new pass FunctionTargetTransformInfo. This pass serves as a 2014-09-18 00:34:14 +00:00
InstCount.cpp [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE 2014-04-22 02:48:03 +00:00
InstructionSimplify.cpp InstCombine, InstSimplify: (%X /s C1) /s C2 isn't always 0 when C1 * C2 overflow 2014-10-11 10:20:01 +00:00
Interval.cpp Revert "[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges." 2014-07-21 17:06:51 +00:00
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 Repace SmallPtrSet with SmallPtrSetImpl in function arguments to avoid needing to mention the size. 2014-08-21 05:55:13 +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 [LVI] Add some additional comments about caching and context instructions 2014-10-16 00:40:05 +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 Make use of @llvm.assume in ValueTracking (computeKnownBits, etc.) 2014-09-07 18:57:58 +00:00
LLVMBuild.txt
Loads.cpp Teach the load analysis to allow finding available values which require 2014-10-21 09:00:40 +00:00
LoopInfo.cpp Introduce enum values for previously defined metadata types. (NFC) 2014-10-21 00:13:20 +00:00
LoopPass.cpp Fix assertion in LICM doFinalization() 2014-09-24 16:48:31 +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 PR21145: Teach LLVM about C++14 sized deallocation functions. 2014-10-03 20:17:06 +00:00
MemoryDependenceAnalysis.cpp Silence a -Wsign-compare warning. NFC. 2014-10-02 13:17:11 +00:00
ModuleDebugInfoPrinter.cpp [C++11] Change DebugInfoFinder to use range-based loops 2014-03-18 09:41:07 +00:00
NoAliasAnalysis.cpp Simplify code. No functionality change. 2014-10-05 12:21:57 +00:00
PHITransAddr.cpp Make use of @llvm.assume in ValueTracking (computeKnownBits, etc.) 2014-09-07 18:57:58 +00:00
PostDominators.cpp [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE 2014-04-22 02:48:03 +00:00
PtrUseVisitor.cpp [C++11] Add range based accessors for the Use-Def chain of a Value. 2014-03-09 03:16:01 +00:00
README.txt
RegionInfo.cpp Fix msc17 build. RegionInfo::RegionInfo::recalculate() doesn't make sense. 2014-07-20 03:57:51 +00:00
RegionPass.cpp Templatify RegionInfo so it works on MachineBasicBlocks 2014-07-19 18:29:29 +00:00
RegionPrinter.cpp Templatify RegionInfo so it works on MachineBasicBlocks 2014-07-19 18:29:29 +00:00
ScalarEvolution.cpp Revert "r219834 - Teach ScalarEvolution to sharpen range information" 2014-10-15 23:46:04 +00:00
ScalarEvolutionAliasAnalysis.cpp AA metadata refactoring (introduce AAMDNodes) 2014-07-24 12:16:19 +00:00
ScalarEvolutionExpander.cpp Make use of @llvm.assume in ValueTracking (computeKnownBits, etc.) 2014-09-07 18:57:58 +00:00
ScalarEvolutionNormalization.cpp Fix typos in comments, NFC 2014-08-29 21:53:01 +00:00
ScopedNoAliasAA.cpp Add override to overriden virtual methods, remove virtual keywords. 2014-09-03 11:41:21 +00:00
SparsePropagation.cpp [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE 2014-04-22 02:48:03 +00:00
StratifiedSets.h [CFLAA] And even more MSVC fixes 2014-09-02 23:50:01 +00:00
TargetTransformInfo.cpp Ignore annotation function calls in cost computation 2014-09-26 17:48:40 +00:00
Trace.cpp
TypeBasedAliasAnalysis.cpp Add scoped-noalias metadata 2014-07-24 14:25:39 +00:00
ValueTracking.cpp Introduce enum values for previously defined metadata types. (NFC) 2014-10-21 00:13:20 +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))

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