diff --git a/compiler-rt/lib/asan/asan_interceptors.cpp b/compiler-rt/lib/asan/asan_interceptors.cpp
--- a/compiler-rt/lib/asan/asan_interceptors.cpp
+++ b/compiler-rt/lib/asan/asan_interceptors.cpp
@@ -463,6 +463,7 @@
   return REAL(strcpy)(to, from);
 }
 
+#if !SANITIZER_WINDOWS
 INTERCEPTOR(char*, strdup, const char *s) {
   void *ctx;
   ASAN_INTERCEPTOR_ENTER(ctx, strdup);
@@ -479,6 +480,24 @@
   }
   return reinterpret_cast<char*>(new_mem);
 }
+#endif // !SANITIZER_WINDOWS
+
+#if SANITIZER_WINDOWS
+INTERCEPTOR(char*, _strdup, const char *s) {
+  void *ctx;
+  ASAN_INTERCEPTOR_ENTER(ctx, _strdup);
+  if (UNLIKELY(!asan_inited)) return internal_strdup(s);
+  ENSURE_ASAN_INITED();
+  uptr length = REAL(strlen)(s);
+  if (flags()->replace_str) {
+    ASAN_READ_RANGE(ctx, s, length + 1);
+  }
+  GET_STACK_TRACE_MALLOC;
+  void *new_mem = asan_malloc(length + 1, &stack);
+  REAL(memcpy)(new_mem, s, length + 1);
+  return reinterpret_cast<char*>(new_mem);
+}
+#endif // SANITIZER_WINDOWS
 
 #if ASAN_INTERCEPT___STRDUP
 INTERCEPTOR(char*, __strdup, const char *s) {
@@ -664,7 +683,11 @@
   ASAN_INTERCEPT_FUNC(strcpy);
   ASAN_INTERCEPT_FUNC(strncat);
   ASAN_INTERCEPT_FUNC(strncpy);
+#if SANITIZER_WINDOWS
+  ASAN_INTERCEPT_FUNC(_strdup);
+#else
   ASAN_INTERCEPT_FUNC(strdup);
+#endif
 #if ASAN_INTERCEPT___STRDUP
   ASAN_INTERCEPT_FUNC(__strdup);
 #endif
diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -199,12 +199,15 @@
 #endif
 
 // Platform-specific options.
-#if SANITIZER_APPLE
-#define PLATFORM_HAS_DIFFERENT_MEMCPY_AND_MEMMOVE 0
-#elif SANITIZER_WINDOWS64
+#if SANITIZER_APPLE || (SANITIZER_WINDOWS && SANITIZER_X64)
 #define PLATFORM_HAS_DIFFERENT_MEMCPY_AND_MEMMOVE 0
+#define PLATFORM_MEMCPY_MEMMOVE_CAN_BE_FOLDED 0
+#elif SANITIZER_WINDOWS && SANITIZER_I386
+#define PLATFORM_HAS_DIFFERENT_MEMCPY_AND_MEMMOVE 1
+#define PLATFORM_MEMCPY_MEMMOVE_CAN_BE_FOLDED 1
 #else
 #define PLATFORM_HAS_DIFFERENT_MEMCPY_AND_MEMMOVE 1
+#define PLATFORM_MEMCPY_MEMMOVE_CAN_BE_FOLDED 0
 #endif  // SANITIZER_APPLE
 
 #ifndef COMMON_INTERCEPTOR_INITIALIZE_RANGE
@@ -871,16 +874,29 @@
   // N.B.: If we switch this to internal_ we'll have to use internal_memmove
   // due to memcpy being an alias of memmove on OS X.
   void *ctx;
-#if PLATFORM_HAS_DIFFERENT_MEMCPY_AND_MEMMOVE
+#ifndef PLATFORM_HAS_DIFFERENT_MEMCPY_AND_MEMMOVE
+#error "Undefined"
+#endif 
+
+#ifndef PLATFORM_MEMCPY_MEMMOVE_CAN_BE_FOLDED
+#error "Undefined"
+#endif
+#if PLATFORM_HAS_DIFFERENT_MEMCPY_AND_MEMMOVE && \
+      !PLATFORM_MEMCPY_MEMMOVE_CAN_BE_FOLDED
     COMMON_INTERCEPTOR_MEMCPY_IMPL(ctx, dst, src, size);
 #else
     COMMON_INTERCEPTOR_MEMMOVE_IMPL(ctx, dst, src, size);
 #endif
 }
 
+// On i386 Windows memcpy and memmove are implemented identically but they
+// have two different definitions, so they can have distinct locations in
+// memory. This means that memcpy may still needs to be intercepted.
 #define INIT_MEMCPY                                  \
   do {                                               \
-    if (PLATFORM_HAS_DIFFERENT_MEMCPY_AND_MEMMOVE) { \
+    if (PLATFORM_HAS_DIFFERENT_MEMCPY_AND_MEMMOVE || \
+        (PLATFORM_MEMCPY_MEMMOVE_CAN_BE_FOLDED &&    \
+         REAL(memcpy) != REAL(memmove))) {           \
       COMMON_INTERCEPT_FUNCTION(memcpy);             \
     } else {                                         \
       ASSIGN_REAL(memcpy, memmove);                  \
diff --git a/compiler-rt/test/asan/TestCases/Windows/memcpy_sanity.cpp b/compiler-rt/test/asan/TestCases/Windows/memcpy_sanity.cpp
new file mode 100644
--- /dev/null
+++ b/compiler-rt/test/asan/TestCases/Windows/memcpy_sanity.cpp
@@ -0,0 +1,24 @@
+// RUN: %clang_cl_asan %s -Fe%t.icf.ref /clang:-fno-builtin-memcpy /clang:-fno-builtin-memmove /link /OPT:ICF /OPT:REF
+// RUN: %clang_cl_asan %s -Fe%t.noicf.ref /clang:-fno-builtin-memcpy /clang:-fno-builtin-memmove /link /OPT:NOICF /OPT:REF
+// RUN: %clang_cl_asan %s -Fe%t.icf.noref /clang:-fno-builtin-memcpy /clang:-fno-builtin-memmove /link /OPT:ICF /OPT:NOREF
+// RUN: %clang_cl_asan %s -Fe%t.noicf.noref /clang:-fno-builtin-memcpy /clang:-fno-builtin-memmove /link /OPT:NOICF /OPT:NOREF
+// RUN: not %run %t.icf.ref 2>&1 | FileCheck %s
+// RUN: not %run %t.noicf.ref 2>&1 | FileCheck %s
+// RUN: not %run %t.icf.noref 2>&1 | FileCheck %s
+// RUN: not %run %t.noicf.noref 2>&1 | FileCheck %s
+
+#include <string.h>
+
+int main() {
+  int *buf = new int[4];
+
+  memmove(buf + 1, buf, 3 * sizeof(int));
+  memcpy(buf + 1, buf, 3 * sizeof(int));
+
+  delete[] buf;
+
+  memcpy(buf + 1, buf, 3 * sizeof(int));
+  // CHECK: AddressSanitizer: heap-use-after-free
+
+  return 0;
+}
diff --git a/compiler-rt/test/asan/TestCases/Windows/memmove_sanity.cpp b/compiler-rt/test/asan/TestCases/Windows/memmove_sanity.cpp
new file mode 100644
--- /dev/null
+++ b/compiler-rt/test/asan/TestCases/Windows/memmove_sanity.cpp
@@ -0,0 +1,24 @@
+// RUN: %clang_cl_asan %s -Fe%t.icf.ref /clang:-fno-builtin-memcpy /clang:-fno-builtin-memmove /link /OPT:ICF /OPT:REF
+// RUN: %clang_cl_asan %s -Fe%t.noicf.ref /clang:-fno-builtin-memcpy /clang:-fno-builtin-memmove /link /OPT:NOICF /OPT:REF
+// RUN: %clang_cl_asan %s -Fe%t.icf.noref /clang:-fno-builtin-memcpy /clang:-fno-builtin-memmove /link /OPT:ICF /OPT:NOREF
+// RUN: %clang_cl_asan %s -Fe%t.noicf.noref /clang:-fno-builtin-memcpy /clang:-fno-builtin-memmove /link /OPT:NOICF /OPT:NOREF
+// RUN: not %run %t.icf.ref 2>&1 | FileCheck %s
+// RUN: not %run %t.noicf.ref 2>&1 | FileCheck %s
+// RUN: not %run %t.icf.noref 2>&1 | FileCheck %s
+// RUN: not %run %t.noicf.noref 2>&1 | FileCheck %s
+
+#include <string.h>
+
+int main() {
+  int *buf = new int[4];
+
+  memmove(buf + 1, buf, 3 * sizeof(int));
+  memcpy(buf + 1, buf, 3 * sizeof(int));
+
+  delete[] buf;
+
+  memmove(buf + 1, buf, 3 * sizeof(int));
+  // CHECK: AddressSanitizer: heap-use-after-free
+
+  return 0;
+}