llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-12-21 16:31:16 +00:00

History

Chris Lattner 4034e14985 teach GVN to widen integer loads when they are overaligned, when doing an wider load would allow elimination of subsequent loads, and when the wider load is still a native integer type. This eliminates a ton of loads on various benchmarks involving struct fields, though it is somewhat hobbled by clang not being very aggressive about field alignment. This is yet another step along the way towards resolving PR6627. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130390 91177308-0d34-0410-b5e6-96231b3b80d8		2011-04-28 07:29:08 +00:00
..
IPA	Fix a ton of comment typos found by codespell. Patch by	2011-04-15 05:18:47 +00:00
AliasAnalysis.cpp	When analyzing functions known to only access argument pointees,	2011-04-27 18:39:03 +00:00
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
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	Teach BasicAA about arm.neon.vld1 and vst1.	2011-04-27 20:44:28 +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	Don't include Operator.h from InstrTypes.h.	2011-04-11 09:35:34 +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	Fix an off by one error while accessing complex address element of a DIVariable.	2011-04-26 18:24:39 +00:00
DominanceFrontier.cpp
DomPrinter.cpp
InlineCost.cpp	Fix a ton of comment typos found by codespell. Patch by	2011-04-15 05:18:47 +00:00
InstCount.cpp
InstructionSimplify.cpp	Don't include Operator.h from InstrTypes.h.	2011-04-11 09:35:34 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	Avoid creating canonical induction variables for non-native types.	2011-03-18 16:50:32 +00:00
LazyValueInfo.cpp	Remove unused STL header includes.	2011-04-23 19:53:52 +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
LoopInfo.cpp
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
MemoryBuiltins.cpp	Add comments for the demanglings. Correct mangled form of operator delete!	2011-03-17 05:20:12 +00:00
MemoryDependenceAnalysis.cpp	teach GVN to widen integer loads when they are overaligned, when doing an	2011-04-28 07:29:08 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
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
RegionPrinter.cpp	RegionPrinter: Ignore back edges when layouting the graph	2011-02-27 04:11:07 +00:00
ScalarEvolution.cpp	Corrects an old, old typo in a case that doesn't seem to be reached in practice.	2011-04-27 18:17:36 +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	Fix a ton of comment typos found by codespell. Patch by	2011-04-15 05:18:47 +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))

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