Index: test/std/experimental/filesystem/fs.op.funcs/fs.op.last_write_time/last_write_time.pass.cpp
===================================================================
--- test/std/experimental/filesystem/fs.op.funcs/fs.op.last_write_time/last_write_time.pass.cpp
+++ test/std/experimental/filesystem/fs.op.funcs/fs.op.last_write_time/last_write_time.pass.cpp
@@ -72,13 +72,72 @@
     return {st.st_atime, st.st_mtime};
 }
 
-inline bool TimeIsRepresentableAsTimeT(file_time_type tp) {
+namespace {
+bool TestSupportsNegativeTimes() {
+    using namespace std::chrono;
+    std::error_code ec;
+    std::time_t old_write_time, new_write_time;
+    { // WARNING: Do not assert in this scope.
+        scoped_test_env env;
+        const path file = env.create_file("file", 42);
+        old_write_time = LastWriteTime(file);
+        std::error_code ec;
+        file_time_type tp(seconds(-5));
+        fs::last_write_time(file, tp, ec);
+        new_write_time = LastWriteTime(file);
+    }
+    if (ec) {
+        assert(old_write_time == new_write_time);
+        return false;
+    } else {
+        assert(new_write_time <= -5);
+        return true;
+    }
+}
+
+bool TestSupportsMaxTime() {
     using namespace std::chrono;
     using Lim = std::numeric_limits<std::time_t>;
-    auto sec = duration_cast<seconds>(tp.time_since_epoch()).count();
-    return (sec >= Lim::min() && sec <= Lim::max());
+    auto max_sec = duration_cast<seconds>(file_time_type::max().time_since_epoch()).count();
+    if (max_sec > Lim::max()) return false;
+    std::error_code ec;
+    std::time_t old_write_time, new_write_time;
+    { // WARNING: Do not assert in this scope.
+        scoped_test_env env;
+        const path file = env.create_file("file", 42);
+        old_write_time = LastWriteTime(file);
+        file_time_type tp = file_time_type::max();
+        fs::last_write_time(file, tp, ec);
+        new_write_time = LastWriteTime(file);
+    }
+    if (ec) {
+        assert(new_write_time == old_write_time);
+        return false;
+    } else {
+        assert(new_write_time > old_write_time);
+        return true;
+    }
 }
 
+static const bool SupportsNegativeTimes = TestSupportsNegativeTimes();
+static const bool SupportsMaxTime = TestSupportsMaxTime();
+
+} // end namespace
+
+// Check if a time point is representable on a given filesystem. Check that:
+// (A) 'tp' is representable as a time_t
+// (B) 'tp' is non-negative or the filesystem supports negative times.
+// (C) 'tp' is not 'file_time_type::max()' or the filesystem supports the max
+//     value.
+inline bool TimeIsRepresentableByFilesystem(file_time_type tp) {
+    using namespace std::chrono;
+    using Lim = std::numeric_limits<std::time_t>;
+    auto sec = duration_cast<seconds>(tp.time_since_epoch()).count();
+    if (sec < Lim::min() || sec > Lim::max())   return false;
+    else if (sec < 0 && !SupportsNegativeTimes) return false;
+    else if (tp == file_time_type::max() && !SupportsMaxTime) return false;
+    return true;
+}
 
 TEST_SUITE(exists_test_suite)
 
@@ -274,7 +333,7 @@
     last_write_time(p, new_time, ec);
     file_time_type tt = last_write_time(p);
 
-    if (!TimeIsRepresentableAsTimeT(new_time)) {
+    if (!TimeIsRepresentableByFilesystem(new_time)) {
         TEST_CHECK(ec);
         TEST_CHECK(ec != GetTestEC());
         TEST_CHECK(tt == last_time);
@@ -293,7 +352,7 @@
     last_write_time(p, new_time, ec);
     tt = last_write_time(p);
 
-    if (!TimeIsRepresentableAsTimeT(new_time)) {
+    if (!TimeIsRepresentableByFilesystem(new_time)) {
         TEST_CHECK(ec);
         TEST_CHECK(ec != GetTestEC());
         TEST_CHECK(tt == last_time);
@@ -323,7 +382,7 @@
     last_write_time(p, new_time, ec);
     file_time_type tt = last_write_time(p);
 
-    if (!TimeIsRepresentableAsTimeT(new_time)) {
+    if (!TimeIsRepresentableByFilesystem(new_time)) {
         TEST_CHECK(ec);
         TEST_CHECK(ec != GetTestEC());
         TEST_CHECK(tt == last_time);