From fb7d35f22a958747dd3ae8861ae3ce018146131c Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Sat, 2 May 2009 17:43:35 +0000 Subject: [PATCH] When ScalarEvolution is told to forget the trip count for a loop, have it also forget any SCEVs associated with loop-header PHIs in the loop, as they may be dependent on trip count information. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@70633 91177308-0d34-0410-b5e6-96231b3b80d8 --- include/llvm/Analysis/ScalarEvolution.h | 5 +++++ lib/Analysis/ScalarEvolution.cpp | 14 +++++++++++--- 2 files changed, 16 insertions(+), 3 deletions(-) diff --git a/include/llvm/Analysis/ScalarEvolution.h b/include/llvm/Analysis/ScalarEvolution.h index 6ef0b35e35d..a0a7c1e81d2 100644 --- a/include/llvm/Analysis/ScalarEvolution.h +++ b/include/llvm/Analysis/ScalarEvolution.h @@ -333,6 +333,11 @@ namespace llvm { /// expression cannot be evaluated, return UnknownValue itself. SCEVHandle getSCEVAtScope(SCEV *S, const Loop *L); + /// forgetLoopPHIs - Delete the memoized SCEVs associated with the + /// PHI nodes in the given loop. This is used when the trip count of + /// the loop may have changed. + void forgetLoopPHIs(const Loop *L); + public: static char ID; // Pass identification, replacement for typeid ScalarEvolution(); diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp index d458399c055..a6d39541aae 100644 --- a/lib/Analysis/ScalarEvolution.cpp +++ b/lib/Analysis/ScalarEvolution.cpp @@ -2111,9 +2111,7 @@ ScalarEvolution::getBackedgeTakenInfo(const Loop *L) { // conservative estimates made without the benefit // of trip count information. if (ItCount.hasAnyInfo()) - for (BasicBlock::iterator I = L->getHeader()->begin(); - PHINode *PN = dyn_cast(I); ++I) - deleteValueFromRecords(PN); + forgetLoopPHIs(L); } return Pair.first->second; } @@ -2124,6 +2122,16 @@ ScalarEvolution::getBackedgeTakenInfo(const Loop *L) { /// is deleted. void ScalarEvolution::forgetLoopBackedgeTakenCount(const Loop *L) { BackedgeTakenCounts.erase(L); + forgetLoopPHIs(L); +} + +/// forgetLoopPHIs - Delete the memoized SCEVs associated with the +/// PHI nodes in the given loop. This is used when the trip count of +/// the loop may have changed. +void ScalarEvolution::forgetLoopPHIs(const Loop *L) { + for (BasicBlock::iterator I = L->getHeader()->begin(); + PHINode *PN = dyn_cast(I); ++I) + deleteValueFromRecords(PN); } /// ComputeBackedgeTakenCount - Compute the number of times the backedge -- 2.34.1