[MemorySSA] Use SetVector to avoid nondeterminism.

Summary:
Use a SetVector for DeadBlockSet.
Resolves PR42574.

Reviewers: george.burgess.iv, uabelho, dblaikie

Subscribers: jlebar, Prazek, mgrang, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64601

llvm-svn: 365970

1 files changed, 3 insertions, 3 deletions

diff --git a/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp b/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp
index 97153292238..aeac6f548b3 100644
--- a/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp
+++ b/llvm/lib/Transforms/Scalar/SimpleLoopUnswitch.cpp
@@ -1463,8 +1463,8 @@ deleteDeadClonedBlocks(Loop &L, ArrayRef<BasicBlock *> ExitBlocks,
 
   // Remove all MemorySSA in the dead blocks
   if (MSSAU) {
-    SmallPtrSet<BasicBlock *, 16> DeadBlockSet(DeadBlocks.begin(),
-                                               DeadBlocks.end());
+    SmallSetVector<BasicBlock *, 8> DeadBlockSet(DeadBlocks.begin(),
+                                                 DeadBlocks.end());
     MSSAU->removeBlocks(DeadBlockSet);
   }
 
@@ -1482,7 +1482,7 @@ static void deleteDeadBlocksFromLoop(Loop &L,
                                      MemorySSAUpdater *MSSAU) {
   // Find all the dead blocks tied to this loop, and remove them from their
   // successors.
-  SmallPtrSet<BasicBlock *, 16> DeadBlockSet;
+  SmallSetVector<BasicBlock *, 8> DeadBlockSet;
 
   // Start with loop/exit blocks and get a transitive closure of reachable dead
   // blocks.