Fix missing exp2 overflow exception (bug 13871).

6 files changed, 28 insertions, 32 deletions

diff --git a/ChangeLog b/ChangeLog
index d548878..c10024a 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,4 +1,14 @@
-2012-03-20  Joseph Myers  <joseph@codesourcery.com>
+2012-03-21  Joseph Myers  <joseph@codesourcery.com>
+
+	[BZ #13871]
+	* math/w_exp2.c: Do not include <float.h>.
+	(o_threshold, u_threshold): Remove.
+	(__exp2): Calculate result before checking finiteness and calling
+	__kernel_standard.
+	* math/w_exp2f.c: Likewise.
+	* math/w_exp2l.c: Likewise.
+	* math/libm-test.inc (exp2_test): Require overflow exception for
+	1e6 input.
 
 	[BZ #3866]
 	* sysdeps/i386/fpu/e_pow.S (__ieee754_pow): Test for y outside the
diff --git a/NEWS b/NEWS
index df8e1f0..a8a3e57 100644
--- a/NEWS
+++ b/NEWS
@@ -16,7 +16,7 @@ Version 2.16
   13526, 13527, 13528, 13529, 13530, 13531, 13532, 13533, 13547, 13551,
   13552, 13553, 13555, 13559, 13566, 13583, 13618, 13637, 13656, 13658,
   13673, 13695, 13704, 13706, 13726, 13738, 13786, 13792, 13806, 13840,
-  13841, 13844, 13846, 13851, 13852, 13854
+  13841, 13844, 13846, 13851, 13852, 13854, 13871
 
 * ISO C11 support:
 
diff --git a/math/libm-test.inc b/math/libm-test.inc
index 64d12a5..afc6f55 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -3108,8 +3108,7 @@ exp2_test (void)
 
   TEST_f_f (exp2, 10, 1024);
   TEST_f_f (exp2, -1, 0.5);
-  /* Bug 13871: OVERFLOW exception may be missing.  */
-  TEST_f_f (exp2, 1e6, plus_infty, OVERFLOW_EXCEPTION_OK);
+  TEST_f_f (exp2, 1e6, plus_infty, OVERFLOW_EXCEPTION);
   TEST_f_f (exp2, -1e6, 0);
   TEST_f_f (exp2, 0.75L, 1.68179283050742908606225095246642979L);
 
diff --git a/math/w_exp2.c b/math/w_exp2.c
index 7a3b0af..b5d8e25 100644
--- a/math/w_exp2.c
+++ b/math/w_exp2.c
@@ -2,23 +2,19 @@
  * wrapper exp2(x)
  */
 
-#include <float.h>
 #include <math.h>
 #include <math_private.h>
 
-static const double o_threshold = (double) DBL_MAX_EXP;
-static const double u_threshold = (double) (DBL_MIN_EXP - DBL_MANT_DIG - 1);
-
 double
 __exp2 (double x)
 {
-  if (__builtin_expect (islessequal (x, u_threshold)
-			|| isgreater (x, o_threshold), 0)
-      && _LIB_VERSION != _IEEE_ && __finite (x))
+  double z = __ieee754_exp2 (x);
+  if (__builtin_expect (!__finite (z), 0)
+      && __finite (x) && _LIB_VERSION != _IEEE_)
     /* exp2 overflow: 44, exp2 underflow: 45 */
-    return __kernel_standard (x, x, 44 + (x <= o_threshold));
+    return __kernel_standard (x, x, 44 + !!__signbit (x));
 
-  return __ieee754_exp2 (x);
+  return z;
 }
 weak_alias (__exp2, exp2)
 #ifdef NO_LONG_DOUBLE
diff --git a/math/w_exp2f.c b/math/w_exp2f.c
index c4e9e94..7c277ef 100644
--- a/math/w_exp2f.c
+++ b/math/w_exp2f.c
@@ -2,22 +2,18 @@
  * wrapper exp2f(x)
  */
 
-#include <float.h>
 #include <math.h>
 #include <math_private.h>
 
-static const float o_threshold = (float) FLT_MAX_EXP;
-static const float u_threshold = (float) (FLT_MIN_EXP - FLT_MANT_DIG - 1);
-
 float
 __exp2f (float x)
 {
-  if (__builtin_expect (islessequal (x, u_threshold)
-			|| isgreater (x, o_threshold), 0)
-      && _LIB_VERSION != _IEEE_ && __finitef (x))
+  float z = __ieee754_exp2f (x);
+  if (__builtin_expect (!__finitef (z), 0)
+      && __finitef (x) && _LIB_VERSION != _IEEE_)
     /* exp2 overflow: 144, exp2 underflow: 145 */
-    return __kernel_standard_f (x, x, 144 + (x <= o_threshold));
+    return __kernel_standard_f (x, x, 144 + !!__signbitf (x));
 
-  return __ieee754_exp2f (x);
+  return z;
 }
 weak_alias (__exp2f, exp2f)
diff --git a/math/w_exp2l.c b/math/w_exp2l.c
index 442a637..f05a8fe 100644
--- a/math/w_exp2l.c
+++ b/math/w_exp2l.c
@@ -2,23 +2,18 @@
  * wrapper exp2l(x)
  */
 
-#include <float.h>
 #include <math.h>
 #include <math_private.h>
 
-static const long double o_threshold = (long double) LDBL_MAX_EXP;
-static const long double u_threshold
-  = (long double) (LDBL_MIN_EXP - LDBL_MANT_DIG - 1);
-
 long double
 __exp2l (long double x)
 {
-  if (__builtin_expect (islessequal (x, u_threshold)
-			|| isgreater (x, o_threshold), 0)
-      && _LIB_VERSION != _IEEE_ && __finitel (x))
+  long double z = __ieee754_exp2l (x);
+  if (__builtin_expect (!__finitel (z), 0)
+      && __finitel (x) && _LIB_VERSION != _IEEE_)
     /* exp2 overflow: 244, exp2 underflow: 245 */
-    return __kernel_standard (x, x, 244 + (x <= o_threshold));
+    return __kernel_standard (x, x, 244 + !!__signbitl (x));
 
-  return __ieee754_exp2l (x);
+  return z;
 }
 weak_alias (__exp2l, exp2l)