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
diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp
index ccd6d6b..478d047 100644
--- a/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -658,6 +658,19 @@
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<Instruction>(OI))
+ if (!SE.DT->dominates(OInst, IVIncInsertPos)) {
+ IncV = 0;
+ break;
+ }
+ if (!IncV)
+ break;
+ // Advance to the next instruction.
IncV = dyn_cast<Instruction>(IncV->getOperand(0));
if (!IncV)
break;