diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 7fe7fa6..f795871 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -12318,4 +12318,49 @@ pointer_to_zero_sized_aggr_p (tree t)
   return (TYPE_SIZE (t) && integer_zerop (TYPE_SIZE (t)));
 }
 
+/* Read SOURCE_DATE_EPOCH from environment to have a deterministic
+   timestamp to replace embedded current dates to get reproducible
+   results. Returns -1 if SOURCE_DATE_EPOCH is not defined.  */
+long long
+get_source_date_epoch()
+{
+  char *source_date_epoch;
+  unsigned long long epoch;
+  char *endptr;
+
+  source_date_epoch = getenv ("SOURCE_DATE_EPOCH");
+  if (!source_date_epoch)
+    return -1
+
+  errno = 0;
+  epoch = strtoull (source_date_epoch, &endptr, 10);
+  if ((errno == ERANGE && (epoch == ULLONG_MAX || epoch == 0))
+      || (errno != 0 && epoch == 0))
+    {
+      fprintf (stderr, "environment variable $SOURCE_DATE_EPOCH: strtoull: \
+%s\n", xstrerror(errno));
+      exit (EXIT_FAILURE);
+    }
+  if (endptr == source_date_epoch)
+    {
+      fprintf (stderr, "environment variable $SOURCE_DATE_EPOCH: \
+No digits were found: %s\n", endptr);
+      exit (EXIT_FAILURE);
+    }
+  if (*endptr != '\0')
+    {
+      fprintf (stderr, "environment variable $SOURCE_DATE_EPOCH: \
+Trailing garbage: %s\n", endptr);
+      exit (EXIT_FAILURE);
+    }
+  if (epoch > ULONG_MAX)
+    {
+      fprintf (stderr, "environment variable $SOURCE_DATE_EPOCH: \
+value must be smaller than or equal to: %lu but was found to be: \
+%llu \n", ULONG_MAX, epoch);
+      exit (EXIT_FAILURE);
+    }
+  return (long long) epoch;
+}
+
 #include "gt-c-family-c-common.h"
diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h
index cabf452..4b55277 100644
--- a/gcc/c-family/c-common.h
+++ b/gcc/c-family/c-common.h
@@ -1437,4 +1437,10 @@ extern bool contains_cilk_spawn_stmt (tree);
 extern tree cilk_for_number_of_iterations (tree);
 extern bool check_no_cilk (tree, const char *, const char *,
 		           location_t loc = UNKNOWN_LOCATION);
+
+/* Read SOURCE_DATE_EPOCH from environment to have a deterministic
+   timestamp to replace embedded current dates to get reproducible
+   results. Returns -1 if SOURCE_DATE_EPOCH is not defined.  */
+extern long long get_source_date_epoch();
+
 #endif /* ! GCC_C_COMMON_H */
diff --git a/gcc/c-family/c-lex.c b/gcc/c-family/c-lex.c
index bb55be8..9344f66 100644
--- a/gcc/c-family/c-lex.c
+++ b/gcc/c-family/c-lex.c
@@ -402,6 +402,10 @@ c_lex_with_flags (tree *value, location_t *loc, unsigned char *cpp_flags,
   enum cpp_ttype type;
   unsigned char add_flags = 0;
   enum overflow_type overflow = OT_NONE;
+  long long source_date_epoch = -1;
+
+  source_date_epoch = get_source_date_epoch();
+  cpp_init_source_date_epoch(parse_in, source_date_epoch);
 
   timevar_push (TV_CPP);
  retry:
diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h
index 5e08014..9eee80f 100644
--- a/libcpp/include/cpplib.h
+++ b/libcpp/include/cpplib.h
@@ -775,6 +775,9 @@ extern void cpp_init_special_builtins (cpp_reader *);
 /* Set up built-ins like __FILE__.  */
 extern void cpp_init_builtins (cpp_reader *, int);
 
+/* Initialize the source_date_epoch value.  */
+extern void cpp_init_source_date_epoch (cpp_reader *, long long);
+
 /* This is called after options have been parsed, and partially
    processed.  */
 extern void cpp_post_options (cpp_reader *);
diff --git a/libcpp/init.c b/libcpp/init.c
index 45a4d13..dfde0a1 100644
--- a/libcpp/init.c
+++ b/libcpp/init.c
@@ -530,6 +530,13 @@ cpp_init_builtins (cpp_reader *pfile, int hosted)
     _cpp_define_builtin (pfile, "__OBJC__ 1");
 }
 
+/* Initialize the source_date_epoch value.  */
+void
+cpp_init_source_date_epoch (cpp_reader *pfile, long long source_date_epoch)
+{
+  pfile->source_date_epoch = source_date_epoch; 
+}
+
 /* Sanity-checks are dependent on command-line options, so it is
    called as a subroutine of cpp_read_main_file ().  */
 #if ENABLE_CHECKING
diff --git a/libcpp/internal.h b/libcpp/internal.h
index c2d0816..4363d96 100644
--- a/libcpp/internal.h
+++ b/libcpp/internal.h
@@ -502,6 +502,10 @@ struct cpp_reader
   const unsigned char *date;
   const unsigned char *time;
 
+  /* Externally set timestamp to replace current date and time useful for
+     reproducibility.  */
+  long long source_date_epoch;
+
   /* EOF token, and a token forcing paste avoidance.  */
   cpp_token avoid_paste;
   cpp_token eof;
diff --git a/libcpp/macro.c b/libcpp/macro.c
index 1e0a0b5..42beb9c 100644
--- a/libcpp/macro.c
+++ b/libcpp/macro.c
@@ -350,13 +350,20 @@ _cpp_builtin_macro_text (cpp_reader *pfile, cpp_hashnode *node)
 	  time_t tt;
 	  struct tm *tb = NULL;
 
-	  /* (time_t) -1 is a legitimate value for "number of seconds
-	     since the Epoch", so we have to do a little dance to
-	     distinguish that from a genuine error.  */
-	  errno = 0;
-	  tt = time(NULL);
-	  if (tt != (time_t)-1 || errno == 0)
-	    tb = localtime (&tt);
+	  /* Set a reproducible timestamp for __DATE__ and __TIME__ macro
+	     usage if SOURCE_DATE_EPOCH is defined.  */
+	  if (pfile->source_date_epoch != -1)
+	     tb = gmtime ((time_t*) &pfile->source_date_epoch);
+	  else
+	    {
+	      /* (time_t) -1 is a legitimate value for "number of seconds
+		 since the Epoch", so we have to do a little dance to
+		 distinguish that from a genuine error.  */
+	      errno = 0;
+	      tt = time (NULL);
+	      if (tt != (time_t)-1 || errno == 0)
+		tb = localtime (&tt);
+	    }
 
 	  if (tb)
 	    {