2004-11-20 Jakub Jelinek <jakub@redhat.com>

	* sysdeps/ieee754/k_standard.c: Document code 50.
	(__kernel_standard) <case 50>: Avoid raising div-by-zero
	exception again.

2004-11-19  H.J. Lu  <hongjiu.lu@intel.com>

	[BZ #552]
	* math/libm-test.inc (tgamma_test): Update tgamma (0) and
	tgamma (-0).

	* sysdeps/generic/w_tgamma.c (__tgamma): Properly handle
	|x| == 0.
	* sysdeps/generic/w_tgammaf.c (__tgammaf): Likewise.
	* sysdeps/generic/w_tgammal.c (__tgammal): Likewise.
	* sysdeps/ieee754/dbl-64/e_gamma_r.c (__ieee754_gamma_r): Likewise.
	* sysdeps/ieee754/flt-32/e_gammaf_r.c: Likewise.
	* sysdeps/ieee754/ldbl-128/e_gammal_r.c: Likewise.
	* sysdeps/ieee754/ldbl-96/e_gammal_r.c: Likewise.

	* sysdeps/ieee754/k_standard.c (__kernel_standard): Handle
	tgamma (0) and tgamma (-0).

5 files changed, 32 insertions, 15 deletions

diff --git a/sysdeps/ieee754/dbl-64/e_gamma_r.c b/sysdeps/ieee754/dbl-64/e_gamma_r.c
index 4614bcf46e..f32309350c 100644
--- a/sysdeps/ieee754/dbl-64/e_gamma_r.c
+++ b/sysdeps/ieee754/dbl-64/e_gamma_r.c
@@ -1,5 +1,5 @@
 /* Implementation of gamma function according to ISO C.
-   Copyright (C) 1997, 1999, 2001 Free Software Foundation, Inc.
+   Copyright (C) 1997, 1999, 2001, 2004 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
 
@@ -35,9 +35,9 @@ __ieee754_gamma_r (double x, int *signgamp)
 
   if (((hx & 0x7fffffff) | lx) == 0)
     {
-      /* Return value for x == 0 is NaN with invalid exception.  */
+      /* Return value for x == 0 is Inf with divide by zero exception.  */
       *signgamp = 0;
-      return x / x;
+      return 1.0 / x;
     }
   if (hx < 0 && (u_int32_t) hx < 0xfff00000 && __rint (x) == x)
     {
diff --git a/sysdeps/ieee754/flt-32/e_gammaf_r.c b/sysdeps/ieee754/flt-32/e_gammaf_r.c
index d484e0c288..926c84f368 100644
--- a/sysdeps/ieee754/flt-32/e_gammaf_r.c
+++ b/sysdeps/ieee754/flt-32/e_gammaf_r.c
@@ -1,5 +1,5 @@
 /* Implementation of gamma function according to ISO C.
-   Copyright (C) 1997, 1999, 2001 Free Software Foundation, Inc.
+   Copyright (C) 1997, 1999, 2001, 2004 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
 
@@ -34,9 +34,9 @@ __ieee754_gammaf_r (float x, int *signgamp)
 
   if ((hx & 0x7fffffff) == 0)
     {
-      /* Return value for x == 0 is NaN with invalid exception.  */
+      /* Return value for x == 0 is Inf with divide by zero exception.  */
       *signgamp = 0;
-      return x / x;
+      return 1.0 / x;
     }
   if (hx < 0 && (u_int32_t) hx < 0xff800000 && __rintf (x) == x)
     {
diff --git a/sysdeps/ieee754/k_standard.c b/sysdeps/ieee754/k_standard.c
index 6def34bc0c..d8fa2a4493 100644
--- a/sysdeps/ieee754/k_standard.c
+++ b/sysdeps/ieee754/k_standard.c
@@ -90,6 +90,7 @@ static double zero = 0.0;	/* used as const */
  *	47-- exp10 underflow
  *	48-- log2(0)
  *	49-- log2(x<0)
+ *	50-- tgamma(+-0)
  */
 
 
@@ -832,7 +833,7 @@ static double zero = 0.0;	/* used as const */
 	    case 40:
 	    case 140:
 	    case 240:
-		/* gamma(finite) overflow */
+		/* tgamma(finite) overflow */
 		exc.type = OVERFLOW;
 		exc.name = type < 100 ? "tgamma" : (type < 200
 						   ? "tgammaf" : "tgammal");
@@ -846,7 +847,7 @@ static double zero = 0.0;	/* used as const */
 	    case 41:
 	    case 141:
 	    case 241:
-		/* gamma(-integer) or gamma(0) */
+		/* tgamma(-integer) */
 		exc.type = SING;
 		exc.name = type < 100 ? "tgamma" : (type < 200
 						   ? "tgammaf" : "tgammal");
@@ -973,8 +974,24 @@ static double zero = 0.0;	/* used as const */
 		  __set_errno (EDOM);
 		}
 		break;
+	    case 50:
+	    case 150:
+	    case 250:
+		/* tgamma(+-0) */
+		exc.type = SING;
+		exc.name = type < 100 ? "tgamma" : (type < 200
+						    ? "tgammaf" : "tgammal");
+		exc.retval = __copysign (HUGE_VAL, x);
+		if (_LIB_VERSION == _POSIX_)
+		  __set_errno (ERANGE);
+		else if (!matherr(&exc)) {
+		  if (_LIB_VERSION == _SVID_)
+		    (void) WRITE2("tgamma: SING error\n", 18);
+		  __set_errno (ERANGE);
+		}
+		break;
 		
-		/* #### Last used is 49/149/249 ### */
+		/* #### Last used is 50/150/250 ### */
 	}
 	return exc.retval;
 }
diff --git a/sysdeps/ieee754/ldbl-128/e_gammal_r.c b/sysdeps/ieee754/ldbl-128/e_gammal_r.c
index 123b559d08..36f5d45881 100644
--- a/sysdeps/ieee754/ldbl-128/e_gammal_r.c
+++ b/sysdeps/ieee754/ldbl-128/e_gammal_r.c
@@ -1,5 +1,5 @@
 /* Implementation of gamma function according to ISO C.
-   Copyright (C) 1997, 1999, 2002 Free Software Foundation, Inc.
+   Copyright (C) 1997, 1999, 2002, 2004 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997 and
    		  Jakub Jelinek <jj@ultra.linux.cz, 1999.
@@ -36,9 +36,9 @@ __ieee754_gammal_r (long double x, int *signgamp)
 
   if (((hx & 0x7fffffffffffffffLL) | lx) == 0)
     {
-      /* Return value for x == 0 is NaN with invalid exception.  */
+      /* Return value for x == 0 is Inf with divide by zero exception.  */
       *signgamp = 0;
-      return x / x;
+      return 1.0 / x;
     }
   if (hx < 0 && (u_int64_t) hx < 0xffff000000000000ULL && __rintl (x) == x)
     {
diff --git a/sysdeps/ieee754/ldbl-96/e_gammal_r.c b/sysdeps/ieee754/ldbl-96/e_gammal_r.c
index f19a072179..dd956fed95 100644
--- a/sysdeps/ieee754/ldbl-96/e_gammal_r.c
+++ b/sysdeps/ieee754/ldbl-96/e_gammal_r.c
@@ -1,5 +1,5 @@
 /* Implementation of gamma function according to ISO C.
-   Copyright (C) 1997, 1999, 2001, 2003 Free Software Foundation, Inc.
+   Copyright (C) 1997, 1999, 2001, 2003, 2004 Free Software Foundation, Inc.
    This file is part of the GNU C Library.
    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
 
@@ -34,9 +34,9 @@ __ieee754_gammal_r (long double x, int *signgamp)
 
   if (((es & 0x7fff) | hx | lx) == 0)
     {
-      /* Return value for x == 0 is NaN with invalid exception.  */
+      /* Return value for x == 0 is Inf with divide by zero exception.  */
       *signgamp = 0;
-      return x / x;
+      return 1.0 / x;
     }
   if (es == 0xffffffff && ((hx & 0x7fffffff) | lx) == 0)
     {