Index: llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp =================================================================== --- llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp +++ llvm/trunk/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp @@ -481,12 +481,11 @@ static bool runImpl(Function &F, LazyValueInfo *LVI) { bool FnChanged = false; - // Visiting in a pre-order depth-first traversal causes us to simplify early - // blocks before querying later blocks (which require us to analyze early - // blocks). Eagerly simplifying shallow blocks means there is strictly less - // work to do for deep blocks. This also means we don't visit unreachable - // blocks. - for (BasicBlock *BB : depth_first(&F.getEntryBlock())) { + // Visiting in an inverse depth first traversal maximizes reuse of the LVI + // cache, as it currently iterates in depth first order upwards, caching + // overdefined info as it goes. + + for (BasicBlock *BB : inverse_depth_first(&F.getEntryBlock())) { bool BBChanged = false; for (BasicBlock::iterator BI = BB->begin(), BE = BB->end(); BI != BE;) { Instruction *II = &*BI++;