Fix y0 and y1 exception handling for zero input [BZ #21134]

The Bessel functions of the second type (Yn) should raise the "divide
by zero" exception when input is zero (both positive and negative).
Current code gives the right output, but fails to set the exception.
This error is exposed for float, double, and long double when linking
with -lieee.  Without this flag, the error is not exposed, because the
wrappers for these functions, which use __kernel_standard
functionality, set the exception as expected.

Tested for powerpc64le.

	[BZ #21134]
	* sysdeps/ieee754/dbl-64/e_j0.c (__ieee754_y0): Raise the
	"divide by zero" exception when the input is zero.
	* sysdeps/ieee754/dbl-64/e_j1.c (__ieee754_y1): Likewise.
	* sysdeps/ieee754/flt-32/e_j0f.c (__ieee754_y0f): Likewise.
	* sysdeps/ieee754/flt-32/e_j1f.c (__ieee754_y1f): Likewise.
	* sysdeps/ieee754/ldbl-128/e_j0l.c (__ieee754_y0l): Likewise.
	* sysdeps/ieee754/ldbl-128/e_j1l.c (__ieee754_y1l): Likewise.

7 files changed, 17 insertions, 6 deletions

diff --git a/ChangeLog b/ChangeLog
index b040928a33..62961a2940 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2017-02-15  Gabriel F. T. Gomes  <gftg@linux.vnet.ibm.com>
+
+	[BZ #21134]
+	* sysdeps/ieee754/dbl-64/e_j0.c (__ieee754_y0): Raise the
+	"divide by zero" exception when the input is zero.
+	* sysdeps/ieee754/dbl-64/e_j1.c (__ieee754_y1): Likewise.
+	* sysdeps/ieee754/flt-32/e_j0f.c (__ieee754_y0f): Likewise.
+	* sysdeps/ieee754/flt-32/e_j1f.c (__ieee754_y1f): Likewise.
+	* sysdeps/ieee754/ldbl-128/e_j0l.c (__ieee754_y0l): Likewise.
+	* sysdeps/ieee754/ldbl-128/e_j1l.c (__ieee754_y1l): Likewise.
+
 2017-02-15  Joseph Myers  <joseph@codesourcery.com>
 
 	* sysdeps/x86_64/fpu/test-double-vlen2.c: Move most contents to,
diff --git a/sysdeps/ieee754/dbl-64/e_j0.c b/sysdeps/ieee754/dbl-64/e_j0.c
index 9f25aa855e..4b440cf0d0 100644
--- a/sysdeps/ieee754/dbl-64/e_j0.c
+++ b/sysdeps/ieee754/dbl-64/e_j0.c
@@ -169,7 +169,7 @@ __ieee754_y0 (double x)
   if (ix >= 0x7ff00000)
     return one / (x + x * x);
   if ((ix | lx) == 0)
-    return -HUGE_VAL + x;                  /* -inf and overflow exception.  */
+    return -1 / zero; /* -inf and divide by zero exception.  */
   if (hx < 0)
     return zero / (zero * x);
   if (ix >= 0x40000000)         /* |x| >= 2.0 */
diff --git a/sysdeps/ieee754/dbl-64/e_j1.c b/sysdeps/ieee754/dbl-64/e_j1.c
index 4827fbf3d3..eb446fd102 100644
--- a/sysdeps/ieee754/dbl-64/e_j1.c
+++ b/sysdeps/ieee754/dbl-64/e_j1.c
@@ -174,7 +174,7 @@ __ieee754_y1 (double x)
   if (__glibc_unlikely (ix >= 0x7ff00000))
     return one / (x + x * x);
   if (__glibc_unlikely ((ix | lx) == 0))
-    return -HUGE_VAL + x;
+    return -1 / zero; /* -inf and divide by zero exception.  */
   /* -inf and overflow exception.  */;
   if (__glibc_unlikely (hx < 0))
     return zero / (zero * x);
diff --git a/sysdeps/ieee754/flt-32/e_j0f.c b/sysdeps/ieee754/flt-32/e_j0f.c
index bd0b80fdb0..b783dd069d 100644
--- a/sysdeps/ieee754/flt-32/e_j0f.c
+++ b/sysdeps/ieee754/flt-32/e_j0f.c
@@ -105,7 +105,7 @@ __ieee754_y0f(float x)
 	ix = 0x7fffffff&hx;
     /* Y0(NaN) is NaN, y0(-inf) is Nan, y0(inf) is 0, y0(0) is -inf.  */
 	if(ix>=0x7f800000) return  one/(x+x*x);
-	if(ix==0) return -HUGE_VALF+x;  /* -inf and overflow exception.  */
+	if(ix==0) return -1/zero; /* -inf and divide by zero exception.  */
 	if(hx<0) return zero/(zero*x);
 	if(ix >= 0x40000000) {  /* |x| >= 2.0 */
 	/* y0(x) = sqrt(2/(pi*x))*(p0(x)*sin(x0)+q0(x)*cos(x0))
diff --git a/sysdeps/ieee754/flt-32/e_j1f.c b/sysdeps/ieee754/flt-32/e_j1f.c
index f359a3d9ba..805a87d85b 100644
--- a/sysdeps/ieee754/flt-32/e_j1f.c
+++ b/sysdeps/ieee754/flt-32/e_j1f.c
@@ -112,7 +112,7 @@ __ieee754_y1f(float x)
     /* if Y1(NaN) is NaN, Y1(-inf) is NaN, Y1(inf) is 0 */
 	if(__builtin_expect(ix>=0x7f800000, 0)) return  one/(x+x*x);
 	if(__builtin_expect(ix==0, 0))
-		return -HUGE_VALF+x;  /* -inf and overflow exception.  */
+		return -1/zero; /* -inf and divide by zero exception.  */
 	if(__builtin_expect(hx<0, 0)) return zero/(zero*x);
 	if(ix >= 0x40000000) {  /* |x| >= 2.0 */
 		SET_RESTORE_ROUNDF (FE_TONEAREST);
diff --git a/sysdeps/ieee754/ldbl-128/e_j0l.c b/sysdeps/ieee754/ldbl-128/e_j0l.c
index 855b5a578b..fb8d3518ce 100644
--- a/sysdeps/ieee754/ldbl-128/e_j0l.c
+++ b/sysdeps/ieee754/ldbl-128/e_j0l.c
@@ -834,7 +834,7 @@ _Float128
     {
       if (x < 0)
 	return (zero / (zero * x));
-      return -HUGE_VALL + x;
+      return -1 / zero; /* -inf and divide by zero exception.  */
     }
   xx = fabsl (x);
   if (xx <= 0x1p-57)
diff --git a/sysdeps/ieee754/ldbl-128/e_j1l.c b/sysdeps/ieee754/ldbl-128/e_j1l.c
index db8dca0ab1..6fc69faa3c 100644
--- a/sysdeps/ieee754/ldbl-128/e_j1l.c
+++ b/sysdeps/ieee754/ldbl-128/e_j1l.c
@@ -852,7 +852,7 @@ __ieee754_y1l (_Float128 x)
     {
       if (x < 0)
 	return (zero / (zero * x));
-      return -HUGE_VALL + x;
+      return -1 / zero; /* -inf and divide by zero exception.  */
     }
   xx = fabsl (x);
   if (xx <= 0x1p-114)