* intervals.c (offset_intervals): Tell GCC not to worry about length overflow

when negating a negative length.

2 files changed, 7 insertions, 1 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 9a8177bf43f..d01d8fbd727 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -6,6 +6,8 @@
         (CHECK_TOTAL_LENGTH): Remove cast to EMACS_INT; no longer needed.
         * intervals.c (interval_deletion_adjustment): Now returns EMACS_INT.
         All uses changed.
+        (offset_intervals): Tell GCC not to worry about length overflow
+        when negating a negative length.
 
         * alloc.c (overrun_check_malloc, overrun_check_realloc): Now static.
         (overrun_check_free): Likewise.
diff --git a/src/intervals.c b/src/intervals.c
index 8f3840976d0..e72bc146d16 100644
--- a/src/intervals.c
+++ b/src/intervals.c
@@ -39,6 +39,7 @@ along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.  */
 
 #include <config.h>
 #include <setjmp.h>
+#include <intprops.h>
 #include "lisp.h"
 #include "intervals.h"
 #include "buffer.h"
@@ -1435,7 +1436,10 @@ offset_intervals (struct buffer *buffer, EMACS_INT start, EMACS_INT length)
   if (length > 0)
     adjust_intervals_for_insertion (BUF_INTERVALS (buffer), start, length);
   else
-    adjust_intervals_for_deletion (buffer, start, -length);
+    {
+      IF_LINT (if (length < - TYPE_MAXIMUM (EMACS_INT)) abort ();)
+      adjust_intervals_for_deletion (buffer, start, -length);
+    }
 }
 
 /* Merge interval I with its lexicographic successor. The resulting