From 83d577490b1473213b6973236110c28e59127956 Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Sun, 27 Sep 2009 17:46:40 +0000 Subject: [PATCH] Fix SCEVExpander's canonical addrec expansion code to work on loops that aren't in canonical loop-simplify form, since it doesn't itself depend on LoopSimplify. This means handling loops without preheaders and loops with multiple backedges. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82905 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/ScalarEvolutionExpander.cpp | 31 +++++++++--------------- 1 file changed, 12 insertions(+), 19 deletions(-) diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp index fd37d7bc1e3..02cfed7ad01 100644 --- a/lib/Analysis/ScalarEvolutionExpander.cpp +++ b/lib/Analysis/ScalarEvolutionExpander.cpp @@ -680,29 +680,22 @@ Value *SCEVExpander::visitAddRecExpr(const SCEVAddRecExpr *S) { // Create and insert the PHI node for the induction variable in the // specified loop. BasicBlock *Header = L->getHeader(); - BasicBlock *Preheader = L->getLoopPreheader(); PHINode *PN = PHINode::Create(Ty, "indvar", Header->begin()); InsertedValues.insert(PN); - PN->addIncoming(Constant::getNullValue(Ty), Preheader); - pred_iterator HPI = pred_begin(Header); - assert(HPI != pred_end(Header) && "Loop with zero preds???"); - if (!L->contains(*HPI)) ++HPI; - assert(HPI != pred_end(Header) && L->contains(*HPI) && - "No backedge in loop?"); - - // Insert a unit add instruction right before the terminator corresponding - // to the back-edge. Constant *One = ConstantInt::get(Ty, 1); - Instruction *Add = BinaryOperator::CreateAdd(PN, One, "indvar.next", - (*HPI)->getTerminator()); - InsertedValues.insert(Add); - - pred_iterator PI = pred_begin(Header); - if (*PI == Preheader) - ++PI; - PN->addIncoming(Add, *PI); - return PN; + for (pred_iterator HPI = pred_begin(Header), HPE = pred_end(Header); + HPI != HPE; ++HPI) + if (L->contains(*HPI)) { + // Insert a unit add instruction right before the terminator corresponding + // to the back-edge. + Instruction *Add = BinaryOperator::CreateAdd(PN, One, "indvar.next", + (*HPI)->getTerminator()); + InsertedValues.insert(Add); + PN->addIncoming(Add, *HPI); + } else { + PN->addIncoming(Constant::getNullValue(Ty), *HPI); + } } // {0,+,F} --> {0,+,1} * F -- 2.34.1