Index: lib/Transforms/Instrumentation/AddressSanitizer.cpp
===================================================================
--- lib/Transforms/Instrumentation/AddressSanitizer.cpp
+++ lib/Transforms/Instrumentation/AddressSanitizer.cpp
@@ -2158,6 +2158,12 @@
     Initializers[i] = Initializer;
   }
 
+  // Add instrumented globals to llvm.compiler.used list to avoid LTO from
+  // ConstantMerge'ing them.
+  appendToCompilerUsed(
+      M, ArrayRef<GlobalValue *>(cast<GlobalValue *>(NewGlobals.data()),
+                                 NewGlobals.size()));
+
   std::string ELFUniqueModuleId =
       (UseGlobalsGC && TargetTriple.isOSBinFormatELF()) ? getUniqueModuleId(&M)
                                                         : "";
Index: projects/compiler-rt/test/asan/TestCases/lto-odr.cc
===================================================================
--- projects/compiler-rt/test/asan/TestCases/lto-odr.cc
+++ projects/compiler-rt/test/asan/TestCases/lto-odr.cc
@@ -0,0 +1,14 @@
+// RUN: %clangxx_asan -O3 -flto %s -o %t
+// RUN: %run %t 2>&1
+
+// REQUIRES: lto
+
+int main(int argc, const char * argv[]) {
+  struct { long width, height; } a = {16, 16};
+  struct { long width, height; } b = {16, 16};
+
+  // Just to make sure 'a' and 'b' don't get optimized out.
+  asm volatile ("" : : "r" (&a), "r" (&b) );
+
+  return 0;
+}
Index: test/Instrumentation/AddressSanitizer/global_lto_merge.ll
===================================================================
--- test/Instrumentation/AddressSanitizer/global_lto_merge.ll
+++ test/Instrumentation/AddressSanitizer/global_lto_merge.ll
@@ -0,0 +1,30 @@
+; RUN: opt < %s -asan -asan-module -S | FileCheck %s
+; RUN: opt < %s -asan -asan-module -constmerge -S | FileCheck %s
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-apple-macosx10.11.0"
+
+%struct = type { i64, i64 }
+
+@a = private unnamed_addr constant %struct { i64 16, i64 16 }, align 8
+@b = private unnamed_addr constant %struct { i64 16, i64 16 }, align 8
+
+; CHECK: @a = {{.*}} %struct
+; CHECK: @b = {{.*}} %struct
+
+; CHECK: @llvm.compiler.used =
+; CHECK-SAME: i8* bitcast ({ %struct, [48 x i8] }* @a to i8*)
+; CHECK-SAME: i8* bitcast ({ %struct, [48 x i8] }* @b to i8*)
+
+define i32 @main(i32, i8** nocapture readnone) {
+  %3 = alloca %struct, align 8
+  %4 = alloca %struct, align 8
+  %5 = bitcast %struct* %3 to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull %5, i8* bitcast (%struct* @a to i8*), i64 16, i32 8, i1 false)
+  %6 = bitcast %struct* %4 to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i64(i8* nonnull %6, i8* bitcast (%struct* @b to i8*), i64 16, i32 8, i1 false)
+  call void asm sideeffect "", "r,r,~{dirflag},~{fpsr},~{flags}"(%struct* nonnull %3, %struct* nonnull %4)
+  ret i32 0
+}
+
+declare void @llvm.memcpy.p0i8.p0i8.i64(i8* nocapture writeonly, i8* nocapture readonly, i64, i32, i1)