On Tue, 2 Oct 2012, Gabriel Dos Reis wrote:
Whining on this list about libstdc++ internal macros and your dislike
of them is not going to produce anything today or tomorrow.
Other compilers using libstdc++ was just an extra argument. Even if g++
was the only compiler on earth, I would still consider a compile-time test
superior to a configure test. The macro __SIZEOF_INT128__ was invented
precisely for this purpose. Yes, that's just more whining ;-)
On Tue, 2 Oct 2012, Gabriel Dos Reis wrote:
On Tue, Oct 2, 2012 at 8:07 AM, Marc Glisse <marc.gli...@inria.fr> wrote:
Or do you mean:
always call __builtin_llabs (whether we have an llabs or not), and let the
compiler replace it with either (x<0)?-x:x or a library call (I assume it
never does that unless it has seen a corresponding declaration)?
See what we did in c/cmath and c_global/cmath.
Note that llabs is quite different from asin. __builtin_llabs generates an
ABS_EXPR, which will later be expanded either to a special instruction or
to a condition. It never generates a call to llabs (I am not sure exactly
if Paolo's instructions to use llabs meant he wanted an actual library
call). __builtin_asin on the other hand is never expanded inline (except
maybe for special constant input like 0) and expands to a call to the
library function asin.
Would the attached patch be better, assuming it passes testing? For lldiv,
there is no builtin (for good reason).
* include/c_std/cstdlib (abs(long long)): Define with
__builtin_llabs when we have long long.
(abs(__int128)): Define when we have __int128.
(div(long long, long long)): Use lldiv.
--
Marc GlisseIndex: cstdlib
===================================================================
--- cstdlib (revision 191941)
+++ cstdlib (working copy)
@@ -128,21 +128,31 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
using ::strtod;
using ::strtol;
using ::strtoul;
using ::system;
#ifdef _GLIBCXX_USE_WCHAR_T
using ::wcstombs;
using ::wctomb;
#endif // _GLIBCXX_USE_WCHAR_T
inline long
- abs(long __i) { return labs(__i); }
+ abs(long __i) { return __builtin_labs(__i); }
+
+#ifdef _GLIBCXX_USE_LONG_LONG
+ inline long long
+ abs(long long __x) { return __builtin_llabs (__x); }
+#endif
+
+#if !defined(__STRICT_ANSI__) && defined(_GLIBCXX_USE_INT128)
+ inline __int128
+ abs(__int128 __x) { return __x >= 0 ? __x : -__x; }
+#endif
inline ldiv_t
div(long __i, long __j) { return ldiv(__i, __j); }
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
#if _GLIBCXX_USE_C99
#undef _Exit
@@ -161,29 +171,26 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#if !_GLIBCXX_USE_C99_LONG_LONG_DYNAMIC
using ::lldiv_t;
#endif
#if _GLIBCXX_USE_C99_CHECK || _GLIBCXX_USE_C99_DYNAMIC
extern "C" void (_Exit)(int) throw () _GLIBCXX_NORETURN;
#endif
#if !_GLIBCXX_USE_C99_DYNAMIC
using ::_Exit;
#endif
- inline long long
- abs(long long __x) { return __x >= 0 ? __x : -__x; }
-
#if !_GLIBCXX_USE_C99_LONG_LONG_DYNAMIC
using ::llabs;
inline lldiv_t
div(long long __n, long long __d)
- { lldiv_t __q; __q.quot = __n / __d; __q.rem = __n % __d; return __q; }
+ { return ::lldiv (__n, __d); }
using ::lldiv;
#endif
#if _GLIBCXX_USE_C99_LONG_LONG_CHECK || _GLIBCXX_USE_C99_LONG_LONG_DYNAMIC
extern "C" long long int (atoll)(const char *) throw ();
extern "C" long long int
(strtoll)(const char * __restrict, char ** __restrict, int) throw ();
extern "C" unsigned long long int
(strtoull)(const char * __restrict, char ** __restrict, int) throw ();
@@ -198,21 +205,20 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace __gnu_cxx
namespace std
{
#if !_GLIBCXX_USE_C99_LONG_LONG_DYNAMIC
using ::__gnu_cxx::lldiv_t;
#endif
using ::__gnu_cxx::_Exit;
- using ::__gnu_cxx::abs;
#if !_GLIBCXX_USE_C99_LONG_LONG_DYNAMIC
using ::__gnu_cxx::llabs;
using ::__gnu_cxx::div;
using ::__gnu_cxx::lldiv;
#endif
using ::__gnu_cxx::atoll;
using ::__gnu_cxx::strtof;
using ::__gnu_cxx::strtoll;
using ::__gnu_cxx::strtoull;
using ::__gnu_cxx::strtold;
