Revert "Increase the size of this SmallVector in PeepholeOptimizer." (r215340)

That broke the build:

/data/buildslave/clang-amd64-freebsd/src-llvm/lib/CodeGen/PeepholeOptimizer.cpp:729:46: error: non-const lvalue reference to type 'SmallPtrSet<[...], 8>' cannot bind to a value of unrelated type 'SmallPtrSet<[...], 16>'
        Changed |= optimizeExtInstr(MI, MBB, LocalMIs);
                                             ^~~~~~~~
/data/buildslave/clang-amd64-freebsd/src-llvm/lib/CodeGen/PeepholeOptimizer.cpp:265:49: note: passing argument to parameter 'LocalMIs' here
                 SmallPtrSet<MachineInstr*, 8> &LocalMIs) {
                                                ^

llvm-svn: 215341
diff --git a/llvm/lib/CodeGen/PeepholeOptimizer.cpp b/llvm/lib/CodeGen/PeepholeOptimizer.cpp
index 0062b64..768fcf7 100644
--- a/llvm/lib/CodeGen/PeepholeOptimizer.cpp
+++ b/llvm/lib/CodeGen/PeepholeOptimizer.cpp
@@ -687,7 +687,7 @@
     MachineBasicBlock *MBB = &*I;
 
     bool SeenMoveImm = false;
-    SmallPtrSet<MachineInstr*, 16> LocalMIs;
+    SmallPtrSet<MachineInstr*, 8> LocalMIs;
     SmallSet<unsigned, 4> ImmDefRegs;
     DenseMap<unsigned, MachineInstr*> ImmDefMIs;
     SmallSet<unsigned, 16> FoldAsLoadDefCandidates;