Index: compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc
===================================================================
--- compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc
+++ compiler-rt/trunk/lib/tsan/rtl/tsan_interceptors.cc
@@ -711,7 +711,11 @@
   if (res != MAP_FAILED) {
     if (fd > 0)
       FdAccess(thr, pc, fd);
-    MemoryRangeImitateWrite(thr, pc, (uptr)res, sz);
+
+    if (thr->ignore_reads_and_writes == 0)
+      MemoryRangeImitateWrite(thr, pc, (uptr)res, sz);
+    else
+      MemoryResetRange(thr, pc, (uptr)res, sz);
   }
   return res;
 }
@@ -726,7 +730,11 @@
   if (res != MAP_FAILED) {
     if (fd > 0)
       FdAccess(thr, pc, fd);
-    MemoryRangeImitateWrite(thr, pc, (uptr)res, sz);
+
+    if (thr->ignore_reads_and_writes == 0)
+      MemoryRangeImitateWrite(thr, pc, (uptr)res, sz);
+    else
+      MemoryResetRange(thr, pc, (uptr)res, sz);
   }
   return res;
 }
Index: compiler-rt/trunk/test/tsan/ignored-interceptors-mmap.cc
===================================================================
--- compiler-rt/trunk/test/tsan/ignored-interceptors-mmap.cc
+++ compiler-rt/trunk/test/tsan/ignored-interceptors-mmap.cc
@@ -0,0 +1,61 @@
+// RUN: %clangxx_tsan -O0 %s -o %t
+// RUN: not %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-NORMAL
+// RUN: %env_tsan_opts=ignore_interceptors_accesses=1 %run %t 2>&1 | FileCheck %s --check-prefix=CHECK-IGNORE
+
+#include <errno.h>
+#include <sys/mman.h>
+
+#include "test.h"
+
+extern "C" {
+void AnnotateIgnoreReadsBegin(const char *f, int l);
+void AnnotateIgnoreReadsEnd(const char *f, int l);
+void AnnotateIgnoreWritesBegin(const char *f, int l);
+void AnnotateIgnoreWritesEnd(const char *f, int l);
+}
+
+void *global_p;
+
+int mmap_and_ignore_reads_and_writes() {
+  const size_t kSize = sysconf(_SC_PAGESIZE);
+  void *p = mmap(0, kSize, PROT_READ|PROT_WRITE,
+                 MAP_PRIVATE|MAP_ANON, -1, 0);
+  if (p == MAP_FAILED)
+    return printf("mmap failed with %d\n", errno);
+  munmap(p, kSize);
+
+  void *new_p = mmap(p, kSize, PROT_READ|PROT_WRITE,
+                     MAP_PRIVATE|MAP_ANON, -1, 0);
+  if (p == MAP_FAILED || p != new_p)
+    return printf("second mmap failed with %d\n", errno);
+
+  AnnotateIgnoreWritesBegin(__FILE__, __LINE__);
+  global_p = p;
+  AnnotateIgnoreWritesEnd(__FILE__, __LINE__);
+  barrier_wait(&barrier);
+  return 0;
+}
+
+void *Thread(void *a) {
+  barrier_wait(&barrier);
+
+  ((int*)global_p)[1] = 10;
+  printf("Read the zero value from mmapped memory %d\n", ((int*)global_p)[1]);
+  return 0;
+}
+
+int main() {
+  barrier_init(&barrier, 2);
+  pthread_t t;
+  pthread_create(&t, 0, Thread, 0);
+  if (mmap_and_ignore_reads_and_writes())
+    return 1;
+  pthread_join(t, 0);
+  printf("OK\n");
+  return 0;
+}
+
+// CHECK-NORMAL: WARNING: ThreadSanitizer: data race
+// CHECK-NORMAL: OK
+// CHECK-IGNORE_NOT: WARNING: ThreadSanitizer: data race
+// CHECK-IGNORE: OK