llvm-6502/lib/Analysis
James Molloy 72035e9a8e Teach the SLP Vectorizer that keeping some values live over a callsite can have a cost.
Some types, such as 128-bit vector types on AArch64, don't have any callee-saved registers. So if a value needs to stay live over a callsite, it must be spilled and refilled. This cost is now taken into account.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214859 91177308-0d34-0410-b5e6-96231b3b80d8
2014-08-05 12:30:34 +00:00
..
IPA Remove uses of the redundant ".reset(nullptr)" of unique_ptr, in favor of ".reset()" 2014-07-19 01:05:11 +00:00
AliasAnalysis.cpp AA metadata refactoring (introduce AAMDNodes) 2014-07-24 12:16:19 +00:00
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp AA metadata refactoring (introduce AAMDNodes) 2014-07-24 12:16:19 +00:00
AliasDebugger.cpp
AliasSetTracker.cpp AA metadata refactoring (introduce AAMDNodes) 2014-07-24 12:16:19 +00:00
Analysis.cpp Add scoped-noalias metadata 2014-07-24 14:25:39 +00:00
BasicAliasAnalysis.cpp Add @llvm.assume, lowering, and some basic properties 2014-07-25 21:13:35 +00:00
BlockFrequencyInfo.cpp Revert "Introduce a string_ostream string builder facilty" 2014-06-26 22:52:05 +00:00
BlockFrequencyInfoImpl.cpp BFI: Add constructor for Weight 2014-07-12 00:26:00 +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
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 scoped-noalias metadata 2014-07-24 14:25:39 +00:00
CodeMetrics.cpp
ConstantFolding.cpp Look through addrspacecast in IsConstantOffsetFromGlobal 2014-07-14 22:39:26 +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 Templatify DominanceFrontier. 2014-07-12 21:59:52 +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: Simplify (X - (0 - Y)) if the second sub is NUW 2014-07-31 04:49:18 +00:00
Interval.cpp Revert "[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges." 2014-07-21 17:06:51 +00:00
IntervalPartition.cpp
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 Revert "[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges." 2014-07-21 17:06:51 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp Revert "Introduce a string_ostream string builder facilty" 2014-06-26 22:52:05 +00:00
LLVMBuild.txt
Loads.cpp AA metadata refactoring (introduce AAMDNodes) 2014-07-24 12:16:19 +00:00
LoopInfo.cpp Revert "[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges." 2014-07-21 17:06:51 +00:00
LoopPass.cpp Add back functionality removed in r210497. 2014-06-21 02:43:02 +00:00
Makefile
MemDepPrinter.cpp
MemoryBuiltins.cpp [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE 2014-04-22 02:48:03 +00:00
MemoryDependenceAnalysis.cpp AA metadata refactoring (introduce AAMDNodes) 2014-07-24 12:16:19 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp Improve BasicAA CS-CS queries (redux) 2014-07-17 01:28:25 +00:00
PHITransAddr.cpp
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 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 "[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges." 2014-07-21 17:06:51 +00:00
ScalarEvolutionAliasAnalysis.cpp AA metadata refactoring (introduce AAMDNodes) 2014-07-24 12:16:19 +00:00
ScalarEvolutionExpander.cpp Fix ScalarEvolutionExpander when creating a PHI in a block with duplicate predecessors 2014-07-31 19:13:38 +00:00
ScalarEvolutionNormalization.cpp test check-in: added missing parenthesis in comment 2014-05-28 19:03:33 +00:00
ScopedNoAliasAA.cpp Simplify and improve scoped-noalias metadata semantics 2014-07-25 15:50:02 +00:00
SparsePropagation.cpp [Modules] Fix potential ODR violations by sinking the DEBUG_TYPE 2014-04-22 02:48:03 +00:00
TargetTransformInfo.cpp Teach the SLP Vectorizer that keeping some values live over a callsite can have a cost. 2014-08-05 12:30:34 +00:00
Trace.cpp
TypeBasedAliasAnalysis.cpp Add scoped-noalias metadata 2014-07-24 14:25:39 +00:00
ValueTracking.cpp Make use of the align parameter attribute for all pointer arguments 2014-07-22 16:58:55 +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))

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