diff --git a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
--- a/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ b/llvm/lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -365,7 +365,7 @@
 
 static cl::opt<bool> ClOptimizeCallbacks("asan-optimize-callbacks",
                                          cl::desc("Optimize callbacks"),
-                                         cl::Hidden, cl::init(false));
+                                         cl::Hidden, cl::init(true));
 
 static cl::opt<bool> ClOptSameTemp(
     "asan-opt-same-temp", cl::desc("Instrument the same temp just once"),
@@ -2873,6 +2873,7 @@
 
 bool AddressSanitizer::instrumentFunction(Function &F,
                                           const TargetLibraryInfo *TLI) {
+  printf("ZXCV3(%p): %s, %d\n", &F, F.getName().data(), F.getLinkage());
   if (F.getLinkage() == GlobalValue::AvailableExternallyLinkage) return false;
   if (!ClDebugFunc.empty() && ClDebugFunc == F.getName()) return false;
   if (F.getName().startswith("__asan_")) return false;
@@ -2888,6 +2889,8 @@
   // Leave if the function doesn't need instrumentation.
   if (!F.hasFnAttribute(Attribute::SanitizeAddress)) return FunctionModified;
 
+  printf("ZXCV1(%p): %s, %d\n", &F, F.getName().data(), F.getLinkage());
+
   LLVM_DEBUG(dbgs() << "ASAN instrumenting:\n" << F << "\n");
 
   initializeCallbacks(*F.getParent());