TYPE_MAXIMUM: avoid theoretically undefined behavior

[gnulib.git] / m4 / stdint.m4

diff --git a/m4/stdint.m4 b/m4/stdint.m4
index 43e1f70..26654c6 100644 (file)
--- a/m4/stdint.m4
+++ b/m4/stdint.m4
@@ -1,4 +1,4 @@
-# stdint.m4 serial 36
+# stdint.m4 serial 37
 dnl Copyright (C) 2001-2011 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
@@ -145,9 +145,11 @@ uintmax_t j = UINTMAX_MAX;
 
 #include <limits.h> /* for CHAR_BIT */
 #define TYPE_MINIMUM(t) \
-  ((t) ((t) 0 < (t) -1 ? (t) 0 : ~ (t) 0 << (sizeof (t) * CHAR_BIT - 1)))
+  ((t) ((t) 0 < (t) -1 ? (t) 0 : ~ TYPE_MAXIMUM (t)))
 #define TYPE_MAXIMUM(t) \
-  ((t) ((t) 0 < (t) -1 ? (t) -1 : ~ (~ (t) 0 << (sizeof (t) * CHAR_BIT - 1))))
+  ((t) ((t) 0 < (t) -1 \
+        ? (t) -1 \
+        : ((((t) 1 << (sizeof (t) * CHAR_BIT - 2)) - 1) * 2 + 1)))
 struct s {
   int check_PTRDIFF:
       PTRDIFF_MIN == TYPE_MINIMUM (ptrdiff_t)