Re: AC_TYPE_LONG_LONG_INT and AC_TYPE_UNSIGNED_LONG_LONG_INT

[Bruno Haible]

Paul Eggert wrote:
> Bruno Haible <address@hidden> writes:
> 
> > #if ! (-2147483648LL < 0)
> > ...
> > #if ! (-9223372036854775807LL < 0)
> 
> If a compiler can't handle that sort of line, then its bugs are more
> serious, since it's relatively common to do preprocessor checks
> like "#if LLONG_MIN < LONG_MIN".

OK. Actually the Sun C compiler does not have this bug when generating
64-bit code, i.e. when the option -xarch=v9 is used. So the bug affects
only 32-bit builds, which IMO is acceptable.

> How about this idea instead?  We sort-of-combine the tests for
> unsigned long long and for signed long long, so that they always
> return consistent answers. The combined test will be the union of the
> current tests.

Yes, I like the idea.

> One can AC_REQUIRE the other, for example, and use its answer.

But I shudder at the idea of mutual AC_REQUIREs. How about of simply merging
the tests, like this? (Untested.) This is just a proposal; of course the
patch should first go into autoconf.

Btw, isn't that a typo in longlong.m4?
     | (ll < i) | (ll > i)
See ulonglong.m4:
     | ull << i | ull >> i
Is that to test the availability of the runtime routines for shifting or
for comparison? Comparisons will always be inlined by the compiler, no?


2007-10-24  Bruno Haible  <address@hidden>

        * m4/longlong.m4 (_AC_TYPE_LONG_LONG_SNIPPET): New macro, extracted
        from AC_TYPE_LONG_LONG_INT and AC_TYPE_UNSIGNED_LONG_LONG_INT.
        (AC_TYPE_LONG_LONG_INT): Use it.
        * m4/ulonglong.m4 (AC_TYPE_UNSIGNED_LONG_LONG_INT): Likewise.
        * modules/strtoull (Files): Add m4/longlong.m4.
        * modules/strtoumax (Files): Likewise.

*** m4/longlong.m4.orig 2007-10-24 13:17:26.000000000 +0200
--- m4/longlong.m4      2007-10-24 13:16:24.000000000 +0200
***************
*** 1,4 ****
! # longlong.m4 serial 11
  dnl Copyright (C) 1999-2007 Free Software Foundation, Inc.
  dnl This file is free software; the Free Software Foundation
  dnl gives unlimited permission to copy and/or distribute it,
--- 1,4 ----
! # longlong.m4 serial 12
  dnl Copyright (C) 1999-2007 Free Software Foundation, Inc.
  dnl This file is free software; the Free Software Foundation
  dnl gives unlimited permission to copy and/or distribute it,
***************
*** 18,36 ****
  [
    AC_CACHE_CHECK([for long long int], [ac_cv_type_long_long_int],
      [AC_LINK_IFELSE(
!        [AC_LANG_PROGRAM(
!         [[#if ! (-9223372036854775807LL < 0 && 0 < 9223372036854775807ll)
!             error in preprocessor;
!           #endif
!           long long int ll = 9223372036854775807ll;
!           long long int nll = -9223372036854775807LL;
!           typedef int a[((-9223372036854775807LL < 0
!                           && 0 < 9223372036854775807ll)
!                          ? 1 : -1)];
!           int i = 63;]],
!         [[long long int llmax = 9223372036854775807ll;
!           return ((ll << 63) | (ll >> 63) | (ll < i) | (ll > i)
!                   | (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.
--- 18,24 ----
  [
    AC_CACHE_CHECK([for long long int], [ac_cv_type_long_long_int],
      [AC_LINK_IFELSE(
!        [_AC_TYPE_LONG_LONG_SNIPPET],
         [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.
***************
*** 63,68 ****
--- 51,90 ----
    fi
  ])
  
+ # Expands to a C program that can be used to test for simultaneous support
+ # of 'long long' and 'unsigned long long'. We don't want to say that
+ # 'long long' is available if 'unsigned long long' is not, or vice versa,
+ # because too many programs rely on the symmetry between signed and unsigned
+ # integer types (excluding 'bool').
+ AC_DEFUN([_AC_TYPE_LONG_LONG_SNIPPET],
+ [
+   AC_LANG_PROGRAM(
+     [[/* Test preprocessor.  */
+       #if ! (-9223372036854775807LL < 0 && 0 < 9223372036854775807ll)
+         error in preprocessor;
+       #endif
+       #if ! (18446744073709551615ULL <= -1ull)
+         error in preprocessor;
+       #endif
+       /* Test literals.  */
+       long long int ll = 9223372036854775807ll;
+       long long int nll = -9223372036854775807LL;
+       unsigned long long int ull = 18446744073709551615ULL;
+       /* Test constant expressions.   */
+       typedef int a[((-9223372036854775807LL < 0 && 0 < 9223372036854775807ll)
+                    ? 1 : -1)];
+       typedef int b[(18446744073709551615ULL <= (unsigned long long int) -1
+                    ? 1 : -1)];
+       int i = 63;]],
+     [[/* Test availability of runtime routines for shift and division.  */
+       long long int llmax = 9223372036854775807ll;
+       unsigned long long int ullmax = 18446744073709551615ull;
+       return ((ll << 63) | (ll >> 63) | (ll < i) | (ll > i)
+             | (llmax / ll) | (llmax % ll)
+             | (ull << 63) | (ull >> 63) | (ull << i) | (ull >> i)
+             | (ullmax / ull) | (ullmax % ull));]])
+ ])
+ 
  # This macro is obsolescent and should go away soon.
  AC_DEFUN([gl_AC_TYPE_LONG_LONG],
  [
*** m4/ulonglong.m4.orig        2007-10-24 13:17:26.000000000 +0200
--- m4/ulonglong.m4     2007-10-24 13:16:25.000000000 +0200
***************
*** 1,4 ****
! # ulonglong.m4 serial 8
  dnl Copyright (C) 1999-2007 Free Software Foundation, Inc.
  dnl This file is free software; the Free Software Foundation
  dnl gives unlimited permission to copy and/or distribute it,
--- 1,4 ----
! # ulonglong.m4 serial 9
  dnl Copyright (C) 1999-2007 Free Software Foundation, Inc.
  dnl This file is free software; the Free Software Foundation
  dnl gives unlimited permission to copy and/or distribute it,
***************
*** 20,36 ****
    AC_CACHE_CHECK([for unsigned long long int],
      [ac_cv_type_unsigned_long_long_int],
      [AC_LINK_IFELSE(
!        [AC_LANG_PROGRAM(
!         [[#if ! (18446744073709551615ULL <= -1ull)
!             error in preprocessor;
!           #endif
!           unsigned long long int ull = 18446744073709551615ULL;
!           typedef int a[(18446744073709551615ULL <= (unsigned long long int) 
-1
!                          ? 1 : -1)];
!          int i = 63;]],
!         [[unsigned long long int ullmax = 18446744073709551615ull;
!           return (ull << 63 | ull >> 63 | ull << i | ull >> i
!                   | ullmax / ull | ullmax % ull);]])],
         [ac_cv_type_unsigned_long_long_int=yes],
         [ac_cv_type_unsigned_long_long_int=no])])
    if test $ac_cv_type_unsigned_long_long_int = yes; then
--- 20,26 ----
    AC_CACHE_CHECK([for unsigned long long int],
      [ac_cv_type_unsigned_long_long_int],
      [AC_LINK_IFELSE(
!        [_AC_TYPE_LONG_LONG_SNIPPET],
         [ac_cv_type_unsigned_long_long_int=yes],
         [ac_cv_type_unsigned_long_long_int=no])])
    if test $ac_cv_type_unsigned_long_long_int = yes; then
*** modules/strtoull.orig       2007-10-24 13:17:26.000000000 +0200
--- modules/strtoull    2007-10-24 13:07:18.000000000 +0200
***************
*** 4,9 ****
--- 4,10 ----
  Files:
  lib/strtoull.c
  m4/ulonglong.m4
+ m4/longlong.m4
  m4/strtoull.m4
  
  Depends-on:
*** modules/strtoumax.orig      2007-10-24 13:17:26.000000000 +0200
--- modules/strtoumax   2007-10-24 13:07:32.000000000 +0200
***************
*** 4,9 ****
--- 4,10 ----
  Files:
  lib/strtoumax.c
  m4/ulonglong.m4
+ m4/longlong.m4
  m4/strtoumax.m4
  
  Depends-on: