llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-07-23 01:30:19 +00:00

History

Eli Friedman 7c6a5a2c39 When marking a block as being unanalyzable, use "Clobber" on the terminator instead of the first instruction in the block. This is a bit of a hack; "Clobber" isn't really the right marking in the first place. memdep doesn't really have any way of properly expressing "unanalyzable" at the moment. Using it on the terminator is much less ambiguous than using it on an arbitrary instruction, though. In the given testcase, the "Clobber" was pointing to a load, and GVN was incorrectly assuming that meant that the "Clobber" load overlapped the load being analyzed (when they are actually unrelated). The included testcase tests both this commit and r132434. Part two of rdar://9429882. (r132434 was mislabeled.) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132442 91177308-0d34-0410-b5e6-96231b3b80d8		2011-06-02 00:08:52 +00:00
..
IPA	Fix a source of non determinism in FindUsedTypes, use a SetVector instead of a	2011-05-13 05:20:42 +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	Make DecomposeGEPExpression check SimplifyInstruction only	2011-05-24 18:24:08 +00:00
CaptureTracking.cpp	Don't include Operator.h from InstrTypes.h.	2011-04-11 09:35:34 +00:00
CFGPrinter.cpp
CMakeLists.txt
ConstantFolding.cpp	implement PR9315, constant folding exp2 in terms of pow (since hosts without	2011-05-22 22:22:35 +00:00
DbgInfoPrinter.cpp
DebugInfo.cpp
DIBuilder.cpp	Use llvm.dbg.cu named metadata to collect compile units.	2011-05-03 16:18:28 +00:00
DominanceFrontier.cpp
DomPrinter.cpp
InlineCost.cpp	Change condition for determining whether a function is small for inlining metrics so that very long functions	2011-05-24 20:22:24 +00:00
InstCount.cpp
InstructionSimplify.cpp	The comparision "max(x,y)==x" is equivalent to "x>=y". Since the max is	2011-05-07 16:56:49 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	Update this comment.	2011-05-27 18:42:33 +00:00
LazyValueInfo.cpp	llvm.memcpy.* has two distinct associated address spaces; the source address space, and the destination address space. Fix up the interface on MemIntrinsic and MemTransferInst to make this clear, and fix InstructionDereferencesPointer in LazyValueInfo.cpp to use the interface properly.	2011-05-31 20:40:16 +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
Makefile
MemDepPrinter.cpp
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp	When marking a block as being unanalyzable, use "Clobber" on the terminator instead of the first instruction in the block. This is a bit of a hack; "Clobber" isn't really the right marking in the first place. memdep doesn't really have any way of properly expressing "unanalyzable" at the moment. Using it on the terminator is much less ambiguous than using it on an arbitrary instruction, though.	2011-06-02 00:08:52 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
PathNumbering.cpp	Remove unused STL header includes.	2011-04-23 19:53:52 +00:00
PathProfileInfo.cpp
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
RegionPass.cpp	Minor change: Fix the typo in RegionPass.h and RegionPass.cpp.	2011-05-05 13:59:38 +00:00
RegionPrinter.cpp
ScalarEvolution.cpp	SCEV: missing null check fix for r132360, dragonegg crash.	2011-06-01 19:14:56 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp
ScalarEvolutionNormalization.cpp
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	Renamed llvm.x86.sse42.crc32 intrinsics; crc64 doesn't exist.	2011-05-26 23:13:19 +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))

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