* xterm.c (x_draw_underwave): Check for integer overflow.

This pacifies gcc 4.7.0 -Wunsafe-loop-optimizations on x86-64.

2 files changed, 8 insertions, 0 deletions

diff --git a/src/ChangeLog b/src/ChangeLog
index 8baeeadc2d5..662aa5232ab 100644
--- a/src/ChangeLog
+++ b/src/ChangeLog
@@ -1,3 +1,8 @@
+2012-06-17  Paul Eggert  <eggert@cs.ucla.edu>
+
+        * xterm.c (x_draw_underwave): Check for integer overflow.
+        This pacifies gcc 4.7.0 -Wunsafe-loop-optimizations on x86-64.
+
 2012-06-17  Jan Djärv  <jan.h.d@swipnet.se>
 
         * nsterm.m (x_free_frame_resources): Move xfree so freed memory isn't
diff --git a/src/xterm.c b/src/xterm.c
index 914d195778f..fec661625f2 100644
--- a/src/xterm.c
+++ b/src/xterm.c
@@ -2710,6 +2710,9 @@ x_draw_underwave (struct glyph_string *s)
   else
     y2 += dy;
 
+  if (INT_MAX - dx < xmax)
+    abort ();
+
   while (x1 <= xmax)
     {
       XDrawLine (s->display, s->window, s->gc, x1, y1, x2, y2);