[SimplifyCFG] Fix for non-determinism in codegen

Summary: This patch fixes issues in codegen uncovered due to https://reviews.llvm.org/D26718

Reviewers: majnemer, chenli, davide

Reviewed By: davide

Subscribers: davide, arsenm, llvm-commits

Differential Revision: https://reviews.llvm.org/D26726

llvm-svn: 301222
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index e625766..e9152b8 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -3754,7 +3754,7 @@
     if (!isa<DbgInfoIntrinsic>(I))
       return false;
 
-  SmallSet<BasicBlock *, 4> TrivialUnwindBlocks;
+  SmallSetVector<BasicBlock *, 4> TrivialUnwindBlocks;
   auto *PhiLPInst = cast<PHINode>(RI->getValue());
 
   // Check incoming blocks to see if any of them are trivial.