diff options
| -rw-r--r-- | include/llvm/Analysis/ScalarEvolution.h | 3 | ||||
| -rw-r--r-- | lib/Analysis/ScalarEvolution.cpp | 12 |
2 files changed, 9 insertions, 6 deletions
diff --git a/include/llvm/Analysis/ScalarEvolution.h b/include/llvm/Analysis/ScalarEvolution.h index 7404f9c00d..6ef0b35e35 100644 --- a/include/llvm/Analysis/ScalarEvolution.h +++ b/include/llvm/Analysis/ScalarEvolution.h @@ -449,7 +449,8 @@ namespace llvm { SCEVHandle getSCEVAtScope(Value *V, const Loop *L); /// isLoopGuardedByCond - Test whether entry to the loop is protected by - /// a conditional between LHS and RHS. + /// a conditional between LHS and RHS. This is used to help avoid max + /// expressions in loop trip counts. bool isLoopGuardedByCond(const Loop *L, ICmpInst::Predicate Pred, SCEV *LHS, SCEV *RHS); diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp index 252eabe2f2..fbfb0308e3 100644 --- a/lib/Analysis/ScalarEvolution.cpp +++ b/lib/Analysis/ScalarEvolution.cpp @@ -2986,8 +2986,9 @@ SCEVHandle ScalarEvolution::HowFarToNonZero(SCEV *V, const Loop *L) { /// BasicBlock * ScalarEvolution::getPredecessorWithUniqueSuccessorForBB(BasicBlock *BB) { - // If the block has a unique predecessor, the predecessor must have - // no other successors from which BB is reachable. + // If the block has a unique predecessor, then there is no path from the + // predecessor to the block that does not go through the direct edge + // from the predecessor to the block. if (BasicBlock *Pred = BB->getSinglePredecessor()) return Pred; @@ -3002,10 +3003,11 @@ ScalarEvolution::getPredecessorWithUniqueSuccessorForBB(BasicBlock *BB) { } /// isLoopGuardedByCond - Test whether entry to the loop is protected by -/// a conditional between LHS and RHS. +/// a conditional between LHS and RHS. This is used to help avoid max +/// expressions in loop trip counts. bool ScalarEvolution::isLoopGuardedByCond(const Loop *L, - ICmpInst::Predicate Pred, - SCEV *LHS, SCEV *RHS) { + ICmpInst::Predicate Pred, + SCEV *LHS, SCEV *RHS) { BasicBlock *Preheader = L->getLoopPreheader(); BasicBlock *PreheaderDest = L->getHeader(); |