* lib/autoconf/types.m4 (AC_TYPE_LONG_LONG_INT): Detect bug in

Tandem NonStop Kernel (OSS) cc -O circa 2004, reported by
Matthew Woehlke.

diff --git a/ChangeLog b/ChangeLog
index 9a14f1fa661849b5a0f7fcbf988797b109372b07..46c90f7507f4de248042500c52a81eacc1e0176b 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2006-11-07  Paul Eggert  <eggert@cs.ucla.edu>
+
+       * lib/autoconf/types.m4 (AC_TYPE_LONG_LONG_INT): Detect bug in
+       Tandem NonStop Kernel (OSS) cc -O circa 2004, reported by
+       Matthew Woehlke.
+
 2006-10-28  Ralf Wildenhues  <Ralf.Wildenhues@gmx.de>
 
        * tests/torture.at (Configuring subdirectories): Do not skip

diff --git a/lib/autoconf/types.m4 b/lib/autoconf/types.m4
index 606eafebae6c11cf765c41cf061bd15290a315c2..ab2f6b962041b423900ff98280d7c5418e367bc6 100644 (file)
--- a/lib/autoconf/types.m4
+++ b/lib/autoconf/types.m4
@@ -480,10 +480,34 @@ AC_DEFUN([AC_TYPE_LONG_LONG_INT],
            int i = 63;]],
          [[long long int llmax = 9223372036854775807ll;
            return ((ll << 63) | (ll >> 63) | (ll < i) | (ll > i)
-                   | llmax / ll | llmax % ll);]])],
-       [ac_cv_type_long_long_int=yes],
+                   | (llmax / ll) | (llmax % ll));]])],
+       [dnl This catches a bug in Tandem NonStop Kernel (OSS) cc -O circa 2004.
+       dnl If cross compiling, assume the bug isn't important, since
+       dnl nobody cross compiles for this platform as far as we know.
+       AC_RUN_IFELSE(
+         [AC_LANG_PROGRAM(
+            [[@%:@include <limits.h>
+              @%:@ifndef LLONG_MAX
+              @%:@ define HALF \
+                       (1LL << (sizeof (long long int) * CHAR_BIT - 2))
+              @%:@ define LLONG_MAX (HALF - 1 + HALF)
+              @%:@endif]],
+            [[long long int n = 1;
+              int i;
+              for (i = 0; ; i++)
+                {
+                  long long int m = n << i;
+                  if (m >> i != n)
+                    return 1;
+                  if (LLONG_MAX / 2 < m)
+                    break;
+                }
+              return 0;]])],
+         [ac_cv_type_long_long_int=yes],
+         [ac_cv_type_long_long_int=no],
+         [ac_cv_type_long_long_int=cross-compiling])],
        [ac_cv_type_long_long_int=no])])
-  if test $ac_cv_type_long_long_int = yes; then
+  if test $ac_cv_type_long_long_int != no; then
     AC_DEFINE([HAVE_LONG_LONG_INT], 1,
       [Define to 1 if the system has the type `long long int'.])
   fi