llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-10-04 16:01:46 +00:00

History

Dan Gohman 52fddd3e36 Fix the the ceiling-division used in computing the MaxBECount so that it doesn't have trouble with an intermediate add overflowing. Also, be more conservative about the case where the induction variable in an SLT loop exit can step past the RHS of the SLT and overflow in a single step. Make getSignedRange more aggressive, to recover for some common cases which the above fixes pessimized. This addresses rdar://7561161. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94512 91177308-0d34-0410-b5e6-96231b3b80d8		2010-01-26 04:40:18 +00:00
..
IPA	make -fno-rtti the default unless a directory builds with REQUIRES_RTTI.	2010-01-24 20:43:08 +00:00
AliasAnalysis.cpp	Partially address a README by having functionattrs consider calls to	2010-01-06 08:45:52 +00:00
AliasAnalysisCounter.cpp	drop the pass name from the output.	2010-01-22 05:52:51 +00:00
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp	adopt getAdjustedAnalysisPointer in a few more passes.	2010-01-20 20:09:02 +00:00
AliasSetTracker.cpp
Analysis.cpp	"In order to ease automatic bindings generation, it would be helpful if boolean values were distinguishable from integers. The attached patch introduces "typedef int LLVMBool;", and uses LLVMBool instead of int throughout the C API, wherever a boolean value is called for."	2010-01-09 22:27:07 +00:00
BasicAliasAnalysis.cpp	add some new methods to adjust this pointers. Not used yet.	2010-01-20 19:26:14 +00:00
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt
ConstantFolding.cpp	fix PR5978 by peeling the loop so that we avoid shifting the	2010-01-08 19:02:23 +00:00
DbgInfoPrinter.cpp	Remove dead debug info intrinsics.	2010-01-05 01:10:40 +00:00
DebugInfo.cpp	Assert when debug intrinsic insert functions are passed empty arguments	2010-01-26 02:07:38 +00:00
DomPrinter.cpp	Create Generic DOTGraphTraits Printer/Viewer	2010-01-16 10:56:41 +00:00
InlineCost.cpp	Pad my commit stats by reducing indentation in this now separate	2010-01-14 23:00:10 +00:00
InstCount.cpp
InstructionSimplify.cpp
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	Re-implement the main strength-reduction portion of LoopStrengthReduction.	2010-01-21 02:09:26 +00:00
LazyValueInfo.cpp
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
LiveValues.cpp
LoopDependenceAnalysis.cpp
LoopInfo.cpp	Restore dump() methods to Loop and MachineLoop.	2010-01-05 21:08:02 +00:00
LoopPass.cpp	eliminate a bunch more unneeded dynamic_cast's.	2010-01-22 05:37:10 +00:00
Makefile	make -fno-rtti the default unless a directory builds with REQUIRES_RTTI.	2010-01-24 20:43:08 +00:00
MemoryBuiltins.cpp
MemoryDependenceAnalysis.cpp
PHITransAddr.cpp
PointerTracking.cpp
PostDominators.cpp
ProfileEstimatorPass.cpp	adopt getAdjustedAnalysisPointer in a few more passes.	2010-01-20 20:09:02 +00:00
ProfileInfo.cpp	adopt getAdjustedAnalysisPointer in a few more passes.	2010-01-20 20:09:02 +00:00
ProfileInfoLoader.cpp
ProfileInfoLoaderPass.cpp	adopt getAdjustedAnalysisPointer in a few more passes.	2010-01-20 20:09:02 +00:00
ProfileVerifierPass.cpp
README.txt
ScalarEvolution.cpp	Fix the the ceiling-division used in computing the MaxBECount so that it doesn't	2010-01-26 04:40:18 +00:00
ScalarEvolutionAliasAnalysis.cpp	adopt getAdjustedAnalysisPointer in a few more passes.	2010-01-20 20:09:02 +00:00
ScalarEvolutionExpander.cpp	When re-using an existing cast for a user, it's still necessary to call	2010-01-21 10:08:42 +00:00
SparsePropagation.cpp
Trace.cpp
ValueTracking.cpp	teach ComputeNumSignBits to look through PHI nodes.	2010-01-07 23:44:37 +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.

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