Improve integer overflow handling a bit

* src/charset.c (read_hex): Use INT_LEFT_SHIFT_OVERFLOW for clarity.
The machine code is the same on my platform.
* src/doprnt.c (doprnt):
* src/emacs-module.c (module_funcall):
* src/font.c (font_intern_prop):
* src/keyboard.c (Frecursion_depth):
* src/lread.c (read1):
Use WRAPV macros instead of checking overflow by hand.
* src/editfns.c (hi_time, time_arith, decode_time_components):
* src/emacs-module.c (Fmodule_load):
Simplify by using FIXNUM_OVERFLOW_P.
* src/emacs-module.c: Include intprops.h.
* src/xdisp.c (percent99): New function.
(decode_mode_spec): Use it to simplify overflow avoidance and
formatting of %p and %P.

1 files changed, 4 insertions, 6 deletions

diff --git a/src/lread.c b/src/lread.c
index dc7c00bbfae..d3413d16cea 100644
--- a/src/lread.c
+++ b/src/lread.c
@@ -2894,19 +2894,17 @@ read1 (Lisp_Object readcharfun, int *pch, bool first_in_list)
 	{
 	  EMACS_INT n = 0;
 	  Lisp_Object tem;
+	  bool overflow = false;
 
 	  /* Read a non-negative integer.  */
 	  while (c >= '0' && c <= '9')
 	    {
-	      if (MOST_POSITIVE_FIXNUM / 10 < n
-		  || MOST_POSITIVE_FIXNUM < n * 10 + c - '0')
-		n = MOST_POSITIVE_FIXNUM + 1;
-	      else
-		n = n * 10 + c - '0';
+	      overflow |= INT_MULTIPLY_WRAPV (n, 10, &n);
+	      overflow |= INT_ADD_WRAPV (n, c - '0', &n);
 	      c = READCHAR;
 	    }
 
-	  if (n <= MOST_POSITIVE_FIXNUM)
+	  if (!overflow && n <= MOST_POSITIVE_FIXNUM)
 	    {
 	      if (c == 'r' || c == 'R')
 		return read_integer (readcharfun, n);