llvm-6502

mirror of https://github.com/c64scene-ar/llvm-6502.git synced 2024-10-05 22:59:16 +00:00

History

Manman Ren 1a710fdde1 BranchProb: modify the definition of an edge in BranchProbabilityInfo to handle the case of multiple edges from one block to another. A simple example is a switch statement with multiple values to the same destination. The definition of an edge is modified from a pair of blocks to a pair of PredBlock and an index into the successors. Also set the weight correctly when building SelectionDAG from LLVM IR, especially when converting a Switch. IntegersSubsetMapping is updated to calculate the weight for each cluster. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162572 91177308-0d34-0410-b5e6-96231b3b80d8		2012-08-24 18:14:27 +00:00
..
IPA
AliasAnalysis.cpp
AliasAnalysisCounter.cpp
AliasAnalysisEvaluator.cpp
AliasDebugger.cpp
AliasSetTracker.cpp
Analysis.cpp
BasicAliasAnalysis.cpp
BlockFrequencyInfo.cpp
BranchProbabilityInfo.cpp	BranchProb: modify the definition of an edge in BranchProbabilityInfo to handle	2012-08-24 18:14:27 +00:00
CaptureTracking.cpp
CFGPrinter.cpp
CMakeLists.txt
CodeMetrics.cpp
ConstantFolding.cpp	When constant folding GEP expressions, keep the address space information of pointers.	2012-07-30 07:25:20 +00:00
DbgInfoPrinter.cpp
DominanceFrontier.cpp
DomPrinter.cpp
InlineCost.cpp	PR13095: Give an inline cost bonus to functions using byval arguments.	2012-08-07 11:13:19 +00:00
InstCount.cpp
InstructionSimplify.cpp	Fix PR13412, a nasty miscompile due to the interleaved	2012-08-07 10:59:59 +00:00
Interval.cpp
IntervalPartition.cpp
IVUsers.cpp	IVUsers should only generate SCEV's for values that are safe to speculate.	2012-07-13 23:33:05 +00:00
LazyValueInfo.cpp	Reduce duplicated hash map lookups.	2012-08-22 15:37:57 +00:00
LibCallAliasAnalysis.cpp
LibCallSemantics.cpp
Lint.cpp
LLVMBuild.txt
Loads.cpp
LoopDependenceAnalysis.cpp
LoopInfo.cpp	Reduce duplicated hash map lookups.	2012-08-22 15:37:57 +00:00
LoopPass.cpp
Makefile
MemDepPrinter.cpp
MemoryBuiltins.cpp	MemoryBuiltins: Properly guard ObjectSizeOffsetVisitor against cycles in the IR.	2012-08-17 19:26:41 +00:00
MemoryDependenceAnalysis.cpp	MemoryDependenceAnalysis attempts to find the first memory dependency for function calls.	2012-08-13 23:03:43 +00:00
ModuleDebugInfoPrinter.cpp
NoAliasAnalysis.cpp
PathNumbering.cpp	Move llvm/Support/TypeBuilder.h -> llvm/TypeBuilder.h. This completes	2012-07-15 23:45:24 +00:00
PathProfileInfo.cpp
PathProfileVerifier.cpp
PHITransAddr.cpp
PostDominators.cpp
ProfileEstimatorPass.cpp	Fix floating-point divide by zero, in a case where the value was not going to be used anyway.	2012-08-24 00:31:45 +00:00
ProfileInfo.cpp
ProfileInfoLoader.cpp	Remove unused private member variables uncovered by the recent changes to clang's -Wunused-private-field.	2012-07-20 22:05:57 +00:00
ProfileInfoLoaderPass.cpp
ProfileVerifierPass.cpp
README.txt
RegionInfo.cpp	Implement the block_iterator of Region based on df_iterator.	2012-08-02 14:20:02 +00:00
RegionPass.cpp
RegionPrinter.cpp
ScalarEvolution.cpp	Stay rational; don't assert trying to take the square root of a negative value.	2012-08-01 09:14:36 +00:00
ScalarEvolutionAliasAnalysis.cpp
ScalarEvolutionExpander.cpp	Fix a typo (the the => the)	2012-07-23 08:51:15 +00:00
ScalarEvolutionNormalization.cpp
SparsePropagation.cpp
Trace.cpp
TypeBasedAliasAnalysis.cpp
ValueTracking.cpp

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))

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