llvm-6502/lib/Analysis
Dan Gohman 948c8a3e3d When checking whether the special handling for an addrec increment which
doesn't dominate the header is needed, don't check whether the increment
expression has computable loop evolution. While the operands of an
addrec are required to be loop-invariant, they're not required to 
dominate any part of the loop. This fixes PR6914.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@102389 91177308-0d34-0410-b5e6-96231b3b80d8
2010-04-26 21:46:36 +00:00
..
IPA fix callgraph dump to not print 0x0x1234 for nodes. 2010-04-23 18:23:40 +00:00
AliasAnalysis.cpp Partially address a README by having functionattrs consider calls to 2010-01-06 08:45:52 +00:00
AliasAnalysisCounter.cpp Fix a missing newline in debug output. 2010-03-01 17:42:55 +00:00
AliasAnalysisEvaluator.cpp clean up algorithm and remove operand order assumptions 2010-04-08 16:46:24 +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 Revert 101465, it broke internal OpenGL testing. 2010-04-16 23:37:20 +00:00
CaptureTracking.cpp rename use_const_iterator to const_use_iterator for consistency's sake 2010-03-25 23:06:16 +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 Update CMake build. 2010-04-08 18:52:18 +00:00
ConstantFolding.cpp Revert 101465, it broke internal OpenGL testing. 2010-04-16 23:37:20 +00:00
DbgInfoPrinter.cpp Remove dead debug info intrinsics. 2010-01-05 01:10:40 +00:00
DebugInfo.cpp DebugInfoFinder::processModule was foiling my plot by 2010-04-02 20:44:29 +00:00
DomPrinter.cpp Remove dead code in the dotty dominance tree printer. 2010-04-12 15:02:19 +00:00
InlineCost.cpp Revert r101471. For tight recursive functions which have multiple 2010-04-21 00:43:30 +00:00
InstCount.cpp Change dbgs() back to errs() as Chris requested. 2009-12-23 23:29:28 +00:00
InstructionSimplify.cpp move some select simplifications out out instcombine into 2010-04-20 05:32:14 +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 the Expr member from IVUsers. Instead of remembering the expression, 2010-04-19 21:48:58 +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
Lint.cpp Tidy a comment. 2010-04-22 01:30:05 +00:00
LiveValues.cpp rename use_const_iterator to const_use_iterator for consistency's sake 2010-03-25 23:06:16 +00:00
LoopDependenceAnalysis.cpp Define placement new wrappers for BumpPtrAllocator and 2010-03-18 18:49:47 +00:00
LoopInfo.cpp Fix a bunch of namespace polution. 2010-04-15 17:08:50 +00:00
LoopPass.cpp Ok, third time's the charm. No changes from last time except the CMake 2010-04-02 23:17:14 +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 Revert 101465, it broke internal OpenGL testing. 2010-04-16 23:37:20 +00:00
MemoryDependenceAnalysis.cpp Revert 101465, it broke internal OpenGL testing. 2010-04-16 23:37:20 +00:00
PHITransAddr.cpp Reapply r97010, the speculative revert failed. 2010-02-24 08:48:04 +00:00
PointerTracking.cpp Rename isLoopGuardedByCond to isLoopEntryGuardedByCond, to emphasise 2010-04-11 19:27:13 +00:00
PostDominators.cpp Remove unneeded debug in PostDominator runOnFunction() 2010-04-12 15:32:55 +00:00
ProfileEstimatorPass.cpp rename pred_const_iterator to const_pred_iterator for consistency's sake 2010-03-25 23:25:28 +00:00
ProfileInfo.cpp rename pred_const_iterator to const_pred_iterator for consistency's sake 2010-03-25 23:25:28 +00:00
ProfileInfoLoader.cpp Reapplied r81355 with the problems fixed. 2009-09-16 11:35:50 +00:00
ProfileInfoLoaderPass.cpp rename pred_const_iterator to const_pred_iterator for consistency's sake 2010-03-25 23:25:28 +00:00
ProfileVerifierPass.cpp rename pred_const_iterator to const_pred_iterator for consistency's sake 2010-03-25 23:25:28 +00:00
README.txt When checking whether the special handling for an addrec increment which 2010-04-26 21:46:36 +00:00
ScalarEvolution.cpp ScalarEvolution support for <= and >= loops. 2010-04-24 03:09:42 +00:00
ScalarEvolutionAliasAnalysis.cpp Add a comment. 2010-03-01 17:56:04 +00:00
ScalarEvolutionExpander.cpp When checking whether the special handling for an addrec increment which 2010-04-26 21:46:36 +00:00
ScalarEvolutionNormalization.cpp Generalize IVUsers to track arbitrary expressions rather than expressions 2010-04-07 22:27:08 +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 Revert 101465, it broke internal OpenGL testing. 2010-04-16 23:37:20 +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))

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