[src/mpfr.h] Fixed some macros implementing functions.

Macros mpfr_nan_p, mpfr_inf_p, mpfr_zero_p and mpfr_regular_p were
incorrect since they yielded a compilation error when the argument
was of type void *, for instance. Their definition as macros is now
available only with __GNUC__.
The tisnan test r14448 should no longer fail.

Also added a comment for mpfr_sgn, which is correct since documented
as a macro.

git-svn-id: https://scm.gforge.inria.fr/anonscm/svn/mpfr/trunk@14451 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 30 insertions, 5 deletions

diff --git a/src/mpfr.h b/src/mpfr.h
index 396fb9d8c..87316839a 100644
--- a/src/mpfr.h
+++ b/src/mpfr.h
@@ -875,11 +875,36 @@ __MPFR_DECLSPEC int mpfr_total_order_p (mpfr_srcptr, mpfr_srcptr);
    that. */
 /* FIXME: most macros are currently buggy. */
 
-/* Inlining these functions is both faster and smaller */
-#define mpfr_nan_p(_x)      ((_x)->_mpfr_exp == __MPFR_EXP_NAN)
-#define mpfr_inf_p(_x)      ((_x)->_mpfr_exp == __MPFR_EXP_INF)
-#define mpfr_zero_p(_x)     ((_x)->_mpfr_exp == __MPFR_EXP_ZERO)
-#define mpfr_regular_p(_x)  ((_x)->_mpfr_exp >  __MPFR_EXP_INF)
+#if __GNUC__ > 2 || __GNUC_MINOR__ >= 95
+/* We need to make sure that the usual type conversion for function
+   parameters is done. Forcing the correct type with a cast like in
+   ((mpfr_srcptr)(_x))->_mpfr_exp should be avoided since this would
+   hide potential type errors, e.g. if _x has an integer type. */
+#define mpfr_nan_p(_x)                          \
+  __extension__ ({                              \
+      mpfr_srcptr _p = (_x);                    \
+      _p->_mpfr_exp == __MPFR_EXP_NAN;          \
+    })
+#define mpfr_inf_p(_x)                          \
+  __extension__ ({                              \
+      mpfr_srcptr _p = (_x);                    \
+      _p->_mpfr_exp == __MPFR_EXP_INF;          \
+    })
+#define mpfr_zero_p(_x)                         \
+  __extension__ ({                              \
+      mpfr_srcptr _p = (_x);                    \
+      _p->_mpfr_exp == __MPFR_EXP_ZERO;         \
+    })
+#define mpfr_regular_p(_x)                      \
+  __extension__ ({                              \
+      mpfr_srcptr _p = (_x);                    \
+      _p->_mpfr_exp > __MPFR_EXP_INF;           \
+    })
+#endif
+
+/* mpfr_sgn is documented as a macro, thus the following code is fine.
+   But it would be safer to regard it as a function in some future
+   MPFR version. */
 #define mpfr_sgn(_x)                                               \
   ((_x)->_mpfr_exp < __MPFR_EXP_INF ?                              \
    (mpfr_nan_p (_x) ? mpfr_set_erangeflag () : (mpfr_void) 0), 0 : \