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authorJoseph Myers <joseph@codesourcery.com>2015-08-07 23:10:35 +0000
committerJoseph Myers <joseph@codesourcery.com>2015-08-07 23:10:35 +0000
commit37550cb3d6591a8f443467707ec80b4ab5c2e157 (patch)
tree934ef1da0ab3a2cd9d0a23b1645392914e95afcc /sysdeps/ieee754
parentdb2bcbcb631f1c1aa023ef9f23a968e1ac288423 (diff)
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Fix tan missing underflows (bug 16517).
Similar to various other bugs in this area, some tan 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.

	[BZ #16517]
	* sysdeps/ieee754/dbl-64/s_tan.c: Include <float.h>.
	(tan): Force underflow exception for arguments with small absolute
	value.
	* sysdeps/ieee754/flt-32/k_tanf.c: Include <float.h>.
	(__kernel_tanf): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/ieee754/ldbl-128/k_tanl.c: Include <float.h>.
	(__kernel_tanl): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/ieee754/ldbl-128ibm/k_tanl.c: Include <float.h>.
	(__kernel_tanl): Force underflow exception for arguments with
	small absolute value.
	* sysdeps/ieee754/ldbl-96/k_tanl.c: Include <float.h>.
	(__kernel_tanl): Force underflow exception for arguments with
	small absolute value.
	* math/auto-libm-test-in: Add more tests of tan.
	* math/auto-libm-test-out: Regenerated.
Diffstat (limited to 'sysdeps/ieee754')
-rw-r--r--sysdeps/ieee754/dbl-64/s_tan.c6
-rw-r--r--sysdeps/ieee754/flt-32/k_tanf.c13
-rw-r--r--sysdeps/ieee754/ldbl-128/k_tanl.c12
-rw-r--r--sysdeps/ieee754/ldbl-128ibm/k_tanl.c12
-rw-r--r--sysdeps/ieee754/ldbl-96/k_tanl.c12
5 files changed, 51 insertions, 4 deletions
diff --git a/sysdeps/ieee754/dbl-64/s_tan.c b/sysdeps/ieee754/dbl-64/s_tan.c
index dcb4aca2de..b4e3bd2a31 100644
--- a/sysdeps/ieee754/dbl-64/s_tan.c
+++ b/sysdeps/ieee754/dbl-64/s_tan.c
@@ -34,6 +34,7 @@
 /*********************************************************************/
 
 #include <errno.h>
+#include <float.h>
 #include "endian.h"
 #include <dla.h>
 #include "mpa.h"
@@ -91,6 +92,11 @@ tan (double x)
   /* (I) The case abs(x) <= 1.259e-8 */
   if (w <= g1.d)
     {
+      if (w < DBL_MIN)
+	{
+	  double force_underflow = x * x;
+	  math_force_eval (force_underflow);
+	}
       retval = x;
       goto ret;
     }
diff --git a/sysdeps/ieee754/flt-32/k_tanf.c b/sysdeps/ieee754/flt-32/k_tanf.c
index a67f36e283..2f2076d6fe 100644
--- a/sysdeps/ieee754/flt-32/k_tanf.c
+++ b/sysdeps/ieee754/flt-32/k_tanf.c
@@ -17,6 +17,7 @@
 static char rcsid[] = "$NetBSD: k_tanf.c,v 1.4 1995/05/10 20:46:39 jtc Exp $";
 #endif
 
+#include <float.h>
 #include <math.h>
 #include <math_private.h>
 static const float
@@ -48,7 +49,17 @@ float __kernel_tanf(float x, float y, int iy)
 	if(ix<0x39000000)			/* x < 2**-13 */
 	    {if((int)x==0) {			/* generate inexact */
 		if((ix|(iy+1))==0) return one/fabsf(x);
-		else return (iy==1)? x: -one/x;
+		else if (iy == 1)
+		  {
+		    if (fabsf (x) < FLT_MIN)
+		      {
+			float force_underflow = x * x;
+			math_force_eval (force_underflow);
+		      }
+		    return x;
+		  }
+		else
+		  return -one / x;
 	    }
 	    }
 	if(ix>=0x3f2ca140) { 			/* |x|>=0.6744 */
diff --git a/sysdeps/ieee754/ldbl-128/k_tanl.c b/sysdeps/ieee754/ldbl-128/k_tanl.c
index dfba2d9a76..6a6fa9f0a6 100644
--- a/sysdeps/ieee754/ldbl-128/k_tanl.c
+++ b/sysdeps/ieee754/ldbl-128/k_tanl.c
@@ -56,6 +56,7 @@
  *		       = 1 - 2*(tan(y) - (tan(y)^2)/(1+tan(y)))
  */
 
+#include <float.h>
 #include <libc-internal.h>
 #include <math.h>
 #include <math_private.h>
@@ -98,8 +99,17 @@ __kernel_tanl (long double x, long double y, int iy)
 	  if ((ix | u.parts32.w1 | u.parts32.w2 | u.parts32.w3
 	       | (iy + 1)) == 0)
 	    return one / fabs (x);
+	  else if (iy == 1)
+	    {
+	      if (fabsl (x) < LDBL_MIN)
+		{
+		  long double force_underflow = x * x;
+		  math_force_eval (force_underflow);
+		}
+	      return x;
+	    }
 	  else
-	    return (iy == 1) ? x : -one / x;
+	    return -one / x;
 	}
     }
   if (ix >= 0x3ffe5942) /* |x| >= 0.6743316650390625 */
diff --git a/sysdeps/ieee754/ldbl-128ibm/k_tanl.c b/sysdeps/ieee754/ldbl-128ibm/k_tanl.c
index 7f1caeebdf..e50cc88da4 100644
--- a/sysdeps/ieee754/ldbl-128ibm/k_tanl.c
+++ b/sysdeps/ieee754/ldbl-128ibm/k_tanl.c
@@ -56,6 +56,7 @@
  *		       = 1 - 2*(tan(y) - (tan(y)^2)/(1+tan(y)))
  */
 
+#include <float.h>
 #include <libc-internal.h>
 #include <math.h>
 #include <math_private.h>
@@ -98,8 +99,17 @@ __kernel_tanl (long double x, long double y, int iy)
 	{
 	  if ((ix | lx | (iy + 1)) == 0)
 	    return one / fabs (x);
+	  else if (iy == 1)
+	    {
+	      if (fabsl (x) < LDBL_MIN)
+		{
+		  long double force_underflow = x * x;
+		  math_force_eval (force_underflow);
+		}
+	      return x;
+	    }
 	  else
-	    return (iy == 1) ? x : -one / x;
+	    return -one / x;
 	}
     }
   if (ix >= 0x3fe59420) /* |x| >= 0.6743316650390625 */
diff --git a/sysdeps/ieee754/ldbl-96/k_tanl.c b/sysdeps/ieee754/ldbl-96/k_tanl.c
index 31cd236aa2..ae6821d984 100644
--- a/sysdeps/ieee754/ldbl-96/k_tanl.c
+++ b/sysdeps/ieee754/ldbl-96/k_tanl.c
@@ -56,6 +56,7 @@
  *		       = 1 - 2*(tan(y) - (tan(y)^2)/(1+tan(y)))
  */
 
+#include <float.h>
 #include <math.h>
 #include <math_private.h>
 static const long double
@@ -94,8 +95,17 @@ __kernel_tanl (long double x, long double y, int iy)
 	{			/* generate inexact */
 	  if (x == 0 && iy == -1)
 	    return one / fabsl (x);
+	  else if (iy == 1)
+	    {
+	      if (absx < LDBL_MIN)
+		{
+		  long double force_underflow = x * x;
+		  math_force_eval (force_underflow);
+		}
+	      return x;
+	    }
 	  else
-	    return (iy == 1) ? x : -one / x;
+	    return -one / x;
 	}
     }
   if (absx >= 0.6743316650390625L)