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Fix sinh missing underflows (bug 16519) [committed]


Similar to various other bugs in this area, some sinh implementations
do not raise the underflow exception for subnormal arguments, when the
result is tiny and inexact.  This patch forces the exception in a
similar way to previous fixes.

Tested for x86_64, x86, mips64 and powerpc.  Committed.

(auto-libm-test-out diffs omitted below.)

2015-08-06  Joseph Myers  <joseph@codesourcery.com>

	[BZ #16519]
	* sysdeps/ieee754/dbl-64/e_sinh.c: Include <float.h>.
	(__ieee754_sinh): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/ieee754/flt-32/e_sinhf.c: Include <float.h>.
	(__ieee754_sinhf): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/ieee754/ldbl-128/e_sinhl.c: Include <float.h>.
	(__ieee754_sinhl): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/ieee754/ldbl-128ibm/e_sinhl.c: Include <float.h>.
	(__ieee754_sinhl): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/ieee754/ldbl-96/e_sinhl.c: Include <float.h>.
	(__ieee754_sinhl): Force underflow exception for arguments with
	small absolute value.
	* math/auto-libm-test-in: Add more tests of sinh.
	* math/auto-libm-test-out: Regenerated.
	* sysdeps/i386/fpu/libm-test-ulps: Update.

diff --git a/math/auto-libm-test-in b/math/auto-libm-test-in
index c17f6f5..cc9b7fd 100644
--- a/math/auto-libm-test-in
+++ b/math/auto-libm-test-in
@@ -2528,6 +2528,10 @@ sinh 0x7.6e259d2436fc4p-4
 sinh 0x3.d6e088p-4
 sinh -0x7.688eap-4
 sinh -0xd.dce79p-4
+sinh min
+sinh -min
+sinh min_subnorm
+sinh -min_subnorm
 
 sqrt 0
 sqrt -0
diff --git a/sysdeps/i386/fpu/libm-test-ulps b/sysdeps/i386/fpu/libm-test-ulps
index 003be8e..a11dd38 100644
--- a/sysdeps/i386/fpu/libm-test-ulps
+++ b/sysdeps/i386/fpu/libm-test-ulps
@@ -1864,6 +1864,10 @@ ildouble: 2
 ldouble: 2
 
 Function: "sinh_downward":
+double: 1
+float: 1
+idouble: 1
+ifloat: 1
 ildouble: 4
 ldouble: 5
 
@@ -1874,6 +1878,8 @@ ldouble: 4
 Function: "sinh_upward":
 double: 1
 float: 1
+idouble: 1
+ifloat: 1
 ildouble: 4
 ldouble: 5
 
diff --git a/sysdeps/ieee754/dbl-64/e_sinh.c b/sysdeps/ieee754/dbl-64/e_sinh.c
index 4ff28bf..c99d283 100644
--- a/sysdeps/ieee754/dbl-64/e_sinh.c
+++ b/sysdeps/ieee754/dbl-64/e_sinh.c
@@ -32,6 +32,7 @@ static char rcsid[] = "$NetBSD: e_sinh.c,v 1.7 1995/05/10 20:46:13 jtc Exp $";
  *	only sinh(0)=0 is exact for finite x.
  */
 
+#include <float.h>
 #include <math.h>
 #include <math_private.h>
 
@@ -58,10 +59,16 @@ __ieee754_sinh (double x)
   /* |x| in [0,22], return sign(x)*0.5*(E+E/(E+1))) */
   if (ix < 0x40360000)                  /* |x|<22 */
     {
-      if (__glibc_unlikely (ix < 0x3e300000))              /* |x|<2**-28 */
+      if (__glibc_unlikely (ix < 0x3e300000)) {            /* |x|<2**-28 */
+	if (fabs (x) < DBL_MIN)
+	  {
+	    double force_underflow = x * x;
+	    math_force_eval (force_underflow);
+	  }
 	if (shuge + x > one)
 	  return x;
-      /* sinh(tiny) = tiny with inexact */
+	/* sinh(tiny) = tiny with inexact */
+      }
       t = __expm1 (fabs (x));
       if (ix < 0x3ff00000)
 	return h * (2.0 * t - t * t / (t + one));
diff --git a/sysdeps/ieee754/flt-32/e_sinhf.c b/sysdeps/ieee754/flt-32/e_sinhf.c
index 0a3cc90..17c2219 100644
--- a/sysdeps/ieee754/flt-32/e_sinhf.c
+++ b/sysdeps/ieee754/flt-32/e_sinhf.c
@@ -13,6 +13,7 @@
  * ====================================================
  */
 
+#include <float.h>
 #include <math.h>
 #include <math_private.h>
 
@@ -34,8 +35,14 @@ __ieee754_sinhf(float x)
 	if (jx<0) h = -h;
     /* |x| in [0,22], return sign(x)*0.5*(E+E/(E+1))) */
 	if (ix < 0x41b00000) {		/* |x|<22 */
-	    if (__builtin_expect(ix<0x31800000, 0))	/* |x|<2**-28 */
+	    if (__builtin_expect(ix<0x31800000, 0)) {	/* |x|<2**-28 */
+		if (fabsf (x) < FLT_MIN)
+		  {
+		    float force_underflow = x * x;
+		    math_force_eval (force_underflow);
+		  }
 		if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */
+	    }
 	    t = __expm1f(fabsf(x));
 	    if(ix<0x3f800000) return h*((float)2.0*t-t*t/(t+one));
 	    return h*(t+t/(t+one));
diff --git a/sysdeps/ieee754/ldbl-128/e_sinhl.c b/sysdeps/ieee754/ldbl-128/e_sinhl.c
index 1ca3c6e..b0244a8 100644
--- a/sysdeps/ieee754/ldbl-128/e_sinhl.c
+++ b/sysdeps/ieee754/ldbl-128/e_sinhl.c
@@ -53,6 +53,7 @@
  *      only sinhl(0)=0 is exact for finite x.
  */
 
+#include <float.h>
 #include <math.h>
 #include <math_private.h>
 
@@ -86,8 +87,15 @@ __ieee754_sinhl (long double x)
   if (ix <= 0x40044000)
     {
       if (ix < 0x3fc60000) /* |x| < 2^-57 */
-	if (shuge + x > one)
-	  return x;		/* sinh(tiny) = tiny with inexact */
+	{
+	  if (fabsl (x) < LDBL_MIN)
+	    {
+	      long double force_underflow = x * x;
+	      math_force_eval (force_underflow);
+	    }
+	  if (shuge + x > one)
+	    return x;		/* sinh(tiny) = tiny with inexact */
+	}
       t = __expm1l (u.value);
       if (ix < 0x3fff0000)
 	return h * (2.0 * t - t * t / (t + one));
diff --git a/sysdeps/ieee754/ldbl-128ibm/e_sinhl.c b/sysdeps/ieee754/ldbl-128ibm/e_sinhl.c
index 1790bef..08e5d86 100644
--- a/sysdeps/ieee754/ldbl-128ibm/e_sinhl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/e_sinhl.c
@@ -28,6 +28,7 @@
  *	only sinh(0)=0 is exact for finite x.
  */
 
+#include <float.h>
 #include <math.h>
 #include <math_private.h>
 
@@ -52,8 +53,14 @@ __ieee754_sinhl(long double x)
 	if (jx<0) h = -h;
     /* |x| in [0,40], return sign(x)*0.5*(E+E/(E+1))) */
 	if (ix < 0x4044000000000000LL) {	/* |x|<40 */
-	    if (ix<0x3e20000000000000LL)	/* |x|<2**-29 */
+	    if (ix<0x3e20000000000000LL) {	/* |x|<2**-29 */
+		if (fabsl (x) < LDBL_MIN)
+		  {
+		    long double force_underflow = x * x;
+		    math_force_eval (force_underflow);
+		  }
 		if(shuge+x>one) return x;/* sinhl(tiny) = tiny with inexact */
+	    }
 	    t = __expm1l(fabsl(x));
 	    if(ix<0x3ff0000000000000LL) return h*(2.0*t-t*t/(t+one));
 	    w = t/(t+one);
diff --git a/sysdeps/ieee754/ldbl-96/e_sinhl.c b/sysdeps/ieee754/ldbl-96/e_sinhl.c
index 4978f34..de6dff6 100644
--- a/sysdeps/ieee754/ldbl-96/e_sinhl.c
+++ b/sysdeps/ieee754/ldbl-96/e_sinhl.c
@@ -36,6 +36,7 @@ static char rcsid[] = "$NetBSD: $";
  *	only sinhl(0)=0 is exact for finite x.
  */
 
+#include <float.h>
 #include <math.h>
 #include <math_private.h>
 
@@ -58,8 +59,14 @@ __ieee754_sinhl(long double x)
 	if (jx & 0x8000) h = -h;
     /* |x| in [0,25], return sign(x)*0.5*(E+E/(E+1))) */
 	if (ix < 0x4003 || (ix == 0x4003 && i0 <= 0xc8000000)) { /* |x|<25 */
-	    if (ix<0x3fdf)		/* |x|<2**-32 */
+	    if (ix<0x3fdf) {		/* |x|<2**-32 */
+		if (fabsl (x) < LDBL_MIN)
+		  {
+		    long double force_underflow = x * x;
+		    math_force_eval (force_underflow);
+		  }
 		if(shuge+x>one) return x;/* sinh(tiny) = tiny with inexact */
+	    }
 	    t = __expm1l(fabsl(x));
 	    if(ix<0x3fff) return h*(2.0*t-t*t/(t+one));
 	    return h*(t+t/(t+one));

-- 
Joseph S. Myers
joseph@codesourcery.com


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