Changes in directory llvm/lib/Transforms/Scalar:
LoopStrengthReduce.cpp updated: 1.78 -> 1.79 --- Log message: Sort StrideOrder so we can process the smallest strides first. This allows for more IV reuses. --- Diffs of the changes: (+27 -0) LoopStrengthReduce.cpp | 27 +++++++++++++++++++++++++++ 1 files changed, 27 insertions(+) Index: llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp diff -u llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp:1.78 llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp:1.79 --- llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp:1.78 Fri Mar 17 13:52:23 2006 +++ llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp Fri Mar 17 18:44:49 2006 @@ -1199,6 +1199,30 @@ CondUse->isUseOfPostIncrementedValue = true; } +namespace { + // Constant strides come first which in turns are sorted by their absolute + // values. If absolute values are the same, then positive strides comes first. + // e.g. + // 4, -1, X, 1, 2 ==> 1, -1, 2, 4, X + struct StrideCompare { + bool operator()(const SCEVHandle &LHS, const SCEVHandle &RHS) { + SCEVConstant *LHSC = dyn_cast<SCEVConstant>(LHS); + SCEVConstant *RHSC = dyn_cast<SCEVConstant>(RHS); + if (LHSC && RHSC) { + int64_t LV = LHSC->getValue()->getSExtValue(); + int64_t RV = RHSC->getValue()->getSExtValue(); + uint64_t ALV = (LV < 0) ? -LV : LV; + uint64_t ARV = (RV < 0) ? -RV : RV; + if (ALV == ARV) + return LV > RV; + else + return ALV < ARV; + } else + return (LHSC && !RHSC); + } + }; +} + void LoopStrengthReduce::runOnLoop(Loop *L) { // First step, transform all loops nesting inside of this loop. for (LoopInfo::iterator I = L->begin(), E = L->end(); I != E; ++I) @@ -1241,6 +1265,9 @@ // IVsByStride keeps IVs for one particular loop. IVsByStride.clear(); + // Sort the StrideOrder so we process larger strides first. + std::stable_sort(StrideOrder.begin(), StrideOrder.end(), StrideCompare()); + // Note: this processes each stride/type pair individually. All users passed // into StrengthReduceStridedIVUsers have the same type AND stride. Also, // node that we iterate over IVUsesByStride indirectly by using StrideOrder. _______________________________________________ llvm-commits mailing list llvm-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits