Avoid overly large SmallPtrSet/SmallSet

These sets perform linear searching in small mode so it is never a good
idea to use SmallSize/N bigger than 32.

llvm-svn: 259283
diff --git a/llvm/lib/CodeGen/SjLjEHPrepare.cpp b/llvm/lib/CodeGen/SjLjEHPrepare.cpp
index e1f242a..1443661 100644
--- a/llvm/lib/CodeGen/SjLjEHPrepare.cpp
+++ b/llvm/lib/CodeGen/SjLjEHPrepare.cpp
@@ -303,7 +303,7 @@
       }
 
       // Find all of the blocks that this value is live in.
-      SmallPtrSet<BasicBlock *, 64> LiveBBs;
+      SmallPtrSet<BasicBlock *, 32> LiveBBs;
       LiveBBs.insert(Inst->getParent());
       while (!Users.empty()) {
         Instruction *U = Users.back();