Fix this code to avoid dereferencing an end() iterator in
offset distributions it doesn't expect.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@96002 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 73d3f9d..a218af9 100644
--- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -2271,6 +2271,10 @@
const SCEV *Reg = *I;
const ImmMapTy &Imms = Map.find(Reg)->second;
+ // It's not worthwhile looking for reuse if there's only one offset.
+ if (Imms.size() == 1)
+ continue;
+
DEBUG(dbgs() << "Generating cross-use offsets for " << *Reg << ':';
for (ImmMapTy::const_iterator J = Imms.begin(), JE = Imms.end();
J != JE; ++J)
@@ -2299,7 +2303,7 @@
};
for (size_t i = 0, e = array_lengthof(OtherImms); i != e; ++i) {
ImmMapTy::const_iterator M = OtherImms[i];
- if (M == J) continue;
+ if (M == J || M == JE) continue;
// Compute the difference between the two.
int64_t Imm = (uint64_t)JImm - M->first;