llvm-6502/lib/Analysis
Dan Gohman 8566963713 Make LoopSimplify change conditional branches in loop exiting blocks
which branch on undef to branch on a boolean constant for the edge
exiting the loop. This helps ScalarEvolution compute trip counts for
loops.

Teach ScalarEvolution to recognize single-value PHIs, when safe, and
ForgetSymbolicName to forget such single-value PHI nodes as apprpriate
in ForgetSymbolicName.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@97126 91177308-0d34-0410-b5e6-96231b3b80d8
2010-02-25 06:57:05 +00:00
..
IPA There are two ways of checking for a given type, for example isa<PointerType>(T) 2010-02-16 11:11:14 +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 There are two ways of checking for a given type, for example isa<PointerType>(T) 2010-02-16 11:11:14 +00:00
AliasDebugger.cpp adopt getAdjustedAnalysisPointer in a few more passes. 2010-01-20 20:09:02 +00:00
AliasSetTracker.cpp Change dbgs() back to errs() as Chris requested. 2009-12-23 22:49:57 +00:00
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 There are two ways of checking for a given type, for example isa<PointerType>(T) 2010-02-16 11:11:14 +00:00
CaptureTracking.cpp There are two ways of checking for a given type, for example isa<PointerType>(T) 2010-02-16 11:11:14 +00:00
CFGPrinter.cpp Remove includes of Support/Compiler.h that are no longer needed after the 2009-10-25 06:57:41 +00:00
CMakeLists.txt add to cmake 2009-12-04 04:15:36 +00:00
ConstantFolding.cpp Remove the code which constant-folded ptrtoint(inttoptr(x)+c) to 2010-02-23 16:35:41 +00:00
DbgInfoPrinter.cpp Remove dead debug info intrinsics. 2010-01-05 01:10:40 +00:00
DebugInfo.cpp Use line and column number to distinguish two lexical blocks at the same level. 2010-02-16 21:39:34 +00:00
DomPrinter.cpp Create Generic DOTGraphTraits Printer/Viewer 2010-01-16 10:56:41 +00:00
InlineCost.cpp There are two ways of checking for a given type, for example isa<PointerType>(T) 2010-02-16 11:11:14 +00:00
InstCount.cpp Change dbgs() back to errs() as Chris requested. 2009-12-23 23:29:28 +00:00
InstructionSimplify.cpp Constant-fold certain comparisons with infinity and negative infinity. 2010-02-22 04:06:03 +00:00
Interval.cpp Change Pass::print to take a raw ostream instead of std::ostream, 2009-08-23 06:03:38 +00:00
IntervalPartition.cpp Change Pass::print to take a raw ostream instead of std::ostream, 2009-08-23 06:03:38 +00:00
IVUsers.cpp Remove unused variables and parameters. 2010-02-22 04:11:59 +00:00
LazyValueInfo.cpp Convert debug messages to use dbgs(). Generally this means 2009-12-23 20:43:58 +00:00
LibCallAliasAnalysis.cpp LibCallAliasAnalysis doesn't use TargetData. 2009-07-31 20:56:29 +00:00
LibCallSemantics.cpp Remove Value::getNameLen 2009-07-26 08:34:35 +00:00
LiveValues.cpp Fix "the the" and similar typos. 2010-02-10 16:03:48 +00:00
LoopDependenceAnalysis.cpp Convert debug messages to use dbgs(). Generally this means 2009-12-23 20:52:41 +00:00
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 Fix "the the" and similar typos. 2010-02-10 16:03:48 +00:00
MemoryDependenceAnalysis.cpp Reapply r97010, the speculative revert failed. 2010-02-24 08:48:04 +00:00
PHITransAddr.cpp Reapply r97010, the speculative revert failed. 2010-02-24 08:48:04 +00:00
PointerTracking.cpp There are two ways of checking for a given type, for example isa<PointerType>(T) 2010-02-16 11:11:14 +00:00
PostDominators.cpp Convert debug messages to use dbgs(). Generally this means 2009-12-23 21:16:54 +00:00
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 Reapplied r81355 with the problems fixed. 2009-09-16 11:35:50 +00:00
ProfileInfoLoaderPass.cpp adopt getAdjustedAnalysisPointer in a few more passes. 2010-01-20 20:09:02 +00:00
ProfileVerifierPass.cpp Convert debug messages to use dbgs(). Generally this means 2009-12-23 22:10:20 +00:00
README.txt Create a README.txt for lib/Analysis, and add an entry. 2009-09-28 18:38:53 +00:00
ScalarEvolution.cpp Make LoopSimplify change conditional branches in loop exiting blocks 2010-02-25 06:57:05 +00:00
ScalarEvolutionAliasAnalysis.cpp There are two ways of checking for a given type, for example isa<PointerType>(T) 2010-02-16 11:11:14 +00:00
ScalarEvolutionExpander.cpp Fix SCEVExpander's existing PHI reuse checking to recognize the 2010-02-17 02:39:31 +00:00
SparsePropagation.cpp Convert debug messages to use dbgs(). Generally this means 2009-12-23 22:28:01 +00:00
Trace.cpp Convert debug messages to use dbgs(). Generally this means 2009-12-23 22:35:10 +00:00
ValueTracking.cpp There are two ways of checking for a given type, for example isa<PointerType>(T) 2010-02-16 11:11:14 +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.

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