llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2025-02-06 23:32:27 +00:00

History

Hal Finkel 19046ec19c Fix SCEVExpander creating distinct duplicate PHI entries

This fixes SCEVExpander so that it does not create multiple distinct induction
variables for duplicate PHI entries. Specifically, given some code like this:

do.body6:                                         ; preds = %do.body6, %do.body6, %if.then5
  %end.0 = phi i8* [ undef, %if.then5 ], [ %incdec.ptr, %do.body6 ], [ %incdec.ptr, %do.body6 ]
...

Note that it is legal to have multiple entries for a basic block so long as the
associated value is the same. So the above input is okay, but expanding an
AddRec in this loop could produce code like this:

do.body6:                                         ; preds = %do.body6, %do.body6, %if.then5
  %indvar = phi i64 [ %indvar.next, %do.body6 ], [ %indvar.next1, %do.body6 ], [ 0, %if.then5 ]
  %end.0 = phi i8* [ undef, %if.then5 ], [ %incdec.ptr, %do.body6 ], [ %incdec.ptr, %do.body6 ]
...
  %indvar.next = add i64 %indvar, 1
  %indvar.next1 = add i64 %indvar, 1

And this is not legal because there are two PHI entries for %do.body6 each with
a distinct value.

Unfortunately, I don't have an in-tree test case.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@188614 91177308-0d34-0410-b5e6-96231b3b80d8

2013-08-18 00:16:23 +00:00

IPA

Disable inlining between sanitized and non-sanitized functions.

2013-08-08 08:22:39 +00:00

AliasAnalysis.cpp

Reimplement isPotentiallyReachable to make nocapture deduction much stronger.

2013-07-27 01:24:00 +00:00

AliasAnalysisCounter.cpp

…

AliasAnalysisEvaluator.cpp

…

AliasDebugger.cpp

…

AliasSetTracker.cpp

…

Analysis.cpp

…

BasicAliasAnalysis.cpp

Use SmallVectorImpl& instead of SmallVector to avoid repeating small vector size.

2013-07-14 04:42:23 +00:00

BlockFrequencyInfo.cpp

…

BranchProbabilityInfo.cpp

…

CaptureTracking.cpp

…

CFG.cpp

Fix an oversight in isPotentiallyReachable where we wouldn't do any CFG-walking

2013-08-13 00:03:47 +00:00

CFGPrinter.cpp

…

CMakeLists.txt

Also update CMakeLists.txt for r187283.

2013-07-27 01:25:51 +00:00

CodeMetrics.cpp

…

ConstantFolding.cpp

Slightly simplify code with helper functions

2013-08-12 23:15:58 +00:00

CostModel.cpp

Use SmallVectorImpl& instead of SmallVector to avoid repeating small vector size.

2013-07-11 16:22:38 +00:00

DependenceAnalysis.cpp

Remove extraneous semicolon.

2013-08-06 16:40:40 +00:00

DominanceFrontier.cpp

…

DomPrinter.cpp

…

InstCount.cpp

…

InstructionSimplify.cpp

Add ISD::FROUND for libm round()

2013-08-07 22:49:12 +00:00

Interval.cpp

…

IntervalPartition.cpp

…

IVUsers.cpp

…

LazyValueInfo.cpp

…

LibCallAliasAnalysis.cpp

…

LibCallSemantics.cpp

…

Lint.cpp

…

LLVMBuild.txt

…

Loads.cpp

…

LoopInfo.cpp

Add 'const' qualifiers to static const char* variables.

2013-07-16 01:17:10 +00:00

LoopPass.cpp

Comment: try to clarify loop iteration order.

2013-07-20 23:10:31 +00:00

Makefile

…

MemDepPrinter.cpp

…

MemoryBuiltins.cpp

Treat nothrow forms of ::operator delete and ::operator delete[] as

2013-07-21 23:11:42 +00:00

MemoryDependenceAnalysis.cpp

…

ModuleDebugInfoPrinter.cpp

…

NoAliasAnalysis.cpp

…

PathNumbering.cpp

…

PathProfileInfo.cpp

…

PathProfileVerifier.cpp

…

PHITransAddr.cpp

…

PostDominators.cpp

…

ProfileDataLoader.cpp

Use SmallVectorImpl& instead of SmallVector to avoid repeating small vector size.

2013-07-14 04:42:23 +00:00

ProfileDataLoaderPass.cpp

…

ProfileEstimatorPass.cpp

…

ProfileInfo.cpp

…

ProfileInfoLoader.cpp

…

ProfileInfoLoaderPass.cpp

…

ProfileVerifierPass.cpp

…

PtrUseVisitor.cpp

…

README.txt

…

RegionInfo.cpp

…

RegionPass.cpp

…

RegionPrinter.cpp

…

ScalarEvolution.cpp

Fix a severe compile time problem when forming large SCEV expressions.

2013-07-31 02:43:40 +00:00

ScalarEvolutionAliasAnalysis.cpp

…

ScalarEvolutionExpander.cpp

Fix SCEVExpander creating distinct duplicate PHI entries

2013-08-18 00:16:23 +00:00

ScalarEvolutionNormalization.cpp

…

SparsePropagation.cpp

…

TargetTransformInfo.cpp

SimplifyCFG: Use parallel-and and parallel-or mode to consolidate branch conditions

2013-07-27 00:01:07 +00:00

Trace.cpp

…

TypeBasedAliasAnalysis.cpp

…

ValueTracking.cpp

Teach ValueTracking about address spaces

2013-08-10 17:34:08 +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))

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