1 files changed, 5 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index b7d9a258913..8b6e5e34b40 100644
--- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -3939,6 +3939,11 @@ void LSRInstance::GenerateCrossUseConstantOffsets() {
     if (Imms.size() == 1)
       continue;
 
+    // UB: Check for overflow
+    int64_t Res;
+    if (__builtin_saddll_overflow(Imms.begin()->first, std::prev(Imms.end())->first, &Res))
+      continue;
+
     DEBUG(dbgs() << "Generating cross-use offsets for " << *Reg << ':';
           for (const auto &Entry : Imms)
             dbgs() << ' ' << Entry.first;