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b1fceb6006
translation of add with immediate. This allows us
to optimize this function:
void test(int N, double* G) {
long j;
G[1] = 1;
for (j = 1; j < N - 1; j++)
G[j+1] = G[j] + G[j+1];
}
to only do one load every iteration of the loop.
llvm-svn: 90013
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|---|---|---|
| .. | ||
| IPA | ||
| AliasAnalysis.cpp | ||
| AliasAnalysisCounter.cpp | ||
| AliasAnalysisEvaluator.cpp | ||
| AliasDebugger.cpp | ||
| AliasSetTracker.cpp | ||
| Analysis.cpp | ||
| BasicAliasAnalysis.cpp | ||
| CaptureTracking.cpp | ||
| CFGPrinter.cpp | ||
| CMakeLists.txt | ||
| ConstantFolding.cpp | ||
| DbgInfoPrinter.cpp | ||
| DebugInfo.cpp | ||
| DomPrinter.cpp | ||
| InlineCost.cpp | ||
| InstCount.cpp | ||
| InstructionSimplify.cpp | ||
| Interval.cpp | ||
| IntervalPartition.cpp | ||
| IVUsers.cpp | ||
| LazyValueInfo.cpp | ||
| LibCallAliasAnalysis.cpp | ||
| LibCallSemantics.cpp | ||
| LiveValues.cpp | ||
| LoopDependenceAnalysis.cpp | ||
| LoopInfo.cpp | ||
| LoopPass.cpp | ||
| Makefile | ||
| MemoryBuiltins.cpp | ||
| MemoryDependenceAnalysis.cpp | ||
| PointerTracking.cpp | ||
| PostDominators.cpp | ||
| ProfileEstimatorPass.cpp | ||
| ProfileInfo.cpp | ||
| ProfileInfoLoader.cpp | ||
| ProfileInfoLoaderPass.cpp | ||
| ProfileVerifierPass.cpp | ||
| README.txt | ||
| ScalarEvolution.cpp | ||
| ScalarEvolutionAliasAnalysis.cpp | ||
| ScalarEvolutionExpander.cpp | ||
| SparsePropagation.cpp | ||
| Trace.cpp | ||
| ValueTracking.cpp | ||
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.
//===---------------------------------------------------------------------===//