From 9feae9f0de032c66d01d16399a4c5296e38870e3 Mon Sep 17 00:00:00 2001 From: Dan Gohman Date: Wed, 17 Feb 2010 02:39:31 +0000 Subject: [PATCH] Fix SCEVExpander's existing PHI reuse checking to recognize the case where there are loop-invariant instructions somehow left inside the loop, and in a position where they won't dominate the IV increment position. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96448 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Analysis/ScalarEvolutionExpander.cpp | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp index ccd6d6b2778..478d04749e2 100644 --- a/lib/Analysis/ScalarEvolutionExpander.cpp +++ b/lib/Analysis/ScalarEvolutionExpander.cpp @@ -658,6 +658,19 @@ SCEVExpander::getAddRecExprPHILiterally(const SCEVAddRecExpr *Normalized, IncV = 0; break; } + // If any of the operands don't dominate the insert position, bail. + // Addrec operands are always loop-invariant, so this can only happen + // if there are instructions which haven't been hoisted. + for (User::op_iterator OI = IncV->op_begin()+1, + OE = IncV->op_end(); OI != OE; ++OI) + if (Instruction *OInst = dyn_cast(OI)) + if (!SE.DT->dominates(OInst, IVIncInsertPos)) { + IncV = 0; + break; + } + if (!IncV) + break; + // Advance to the next instruction. IncV = dyn_cast(IncV->getOperand(0)); if (!IncV) break; -- 2.34.1