math.c: check argument to lgamma_r

* math.c (math_lgamma): check the argument before calling math
  function `lgamma_r` for edge cases.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58698 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

configure.in

@@ -2639,47 +2639,6 @@ main(int argc, char **argv)
 ])
 AS_IF([test "x$rb_cv_atan2_inf_c99" = xyes], [AC_DEFINE(ATAN2_INF_C99)])
 
-AS_IF([test "x$ac_cv_func_lgamma_r" = xyes], [
-    AC_CACHE_CHECK(whether lgamma_r handles +0.0 and -0.0, rb_cv_lgamma_r_pm0, [
-	AC_TRY_RUN([
-@%:@include <math.h>
-@%:@ifdef HAVE_UNISTD_H
-@%:@include <unistd.h>
-@%:@endif
-@%:@ifndef EXIT_SUCCESS
-@%:@define EXIT_SUCCESS 0
-@%:@endif
-@%:@ifndef EXIT_FAILURE
-@%:@define EXIT_FAILURE 1
-@%:@endif
-
-int
-main(int argc, char **argv)
-{
-    int sign = 0;
-    double x = lgamma_r(-0.0, &sign);
-
-    /* should be [+inf, -1] */
-    if (x <= 0) return EXIT_FAILURE;
-    if (!isinf(x)) return EXIT_FAILURE;
-    if (sign != -1) return EXIT_FAILURE;
-
-    /* should be [+inf, 1] */
-    x = lgamma_r(+0.0, &sign);
-    if (x <= 0) return EXIT_FAILURE;
-    if (!isinf(x)) return EXIT_FAILURE;
-    if (sign != 1) return EXIT_FAILURE;
-    return EXIT_SUCCESS;
-}
-],
-	[rb_cv_lgamma_r_pm0=yes],
-	[rb_cv_lgamma_r_pm0=no],
-	[rb_cv_lgamma_r_pm0=yes]
-	)
-    ])
-    AS_IF([test "x$rb_cv_lgamma_r_pm0" = xno], [AC_DEFINE(LGAMMA_R_PM0_FIX)])
-])
-
 # Some platform need -lrt for clock_gettime, but the other don't.
 if test x"$ac_cv_func_clock_gettime" != xyes; then
     # glibc 2.17 moves clock_* functions from librt to the main C library.

math.c

@@ -778,22 +778,6 @@ math_erfc(VALUE unused_obj, VALUE x)
     return DBL2NUM(erfc(Get_Double(x)));
 }
 
-#if defined LGAMMA_R_PM0_FIX
-static inline double
-ruby_lgamma_r(const double d, int *sign)
-{
-    const double g = lgamma_r(d, sign);
-    if (isinf(g)) {
-	if (d == 0.0) {
-	    *sign = signbit(d) ? -1 : +1;
-	    return INFINITY;
-	}
-    }
-    return g;
-}
-#define lgamma_r(d, sign) ruby_lgamma_r(d, sign)
-#endif
-
 /*
  * call-seq:
  *    Math.gamma(x)  -> Float
@@ -911,6 +895,10 @@ math_lgamma(VALUE unused_obj, VALUE x)
 	if (signbit(d)) domain_error("lgamma");
 	return rb_assoc_new(DBL2NUM(INFINITY), INT2FIX(1));
     }
+    if (d == 0.0) {
+	VALUE vsign = signbit(d) ? INT2FIX(-1) : INT2FIX(+1);
+	return rb_assoc_new(DBL2NUM(INFINITY), vsign);
+    }
     v = DBL2NUM(lgamma_r(d, &sign));
     return rb_assoc_new(v, INT2FIX(sign));
 }