Fix exp10 errno setting on underflow (bug 6787).

6 files changed, 26 insertions, 16 deletions

diff --git a/ChangeLog b/ChangeLog
index 25e7725bf2..80a65ea1c7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
 2013-11-29  Joseph Myers  <joseph@codesourcery.com>
 
+	[BZ #6787]
+	* math/w_exp10.c (__exp10): Handle a zero result as underflow.
+	* math/w_exp10f.c (__exp10f): Likewise.
+	* math/w_exp10l.c (__exp10l): Likewise.
+	* math/libm-test.inc (exp10_test_data): Add more tests and expect
+	errno settings in existing tests.
+
 	[BZ #14032]
 	* sysdeps/i386/fpu/e_sqrt.S (__ieee754_sqrt): Do fsqrt with
 	precision control set to double precision.
diff --git a/NEWS b/NEWS
index 0115c8fec1..e85b4c6e30 100644
--- a/NEWS
+++ b/NEWS
@@ -9,17 +9,18 @@ Version 2.19
 
 * The following bugs are resolved with this release:
 
-  156, 387, 431, 832, 2801, 7003, 9954, 10253, 10278, 11087, 11157, 11214,
-  13028, 13982, 13985, 14029, 14032, 14143, 14155, 14547, 14699, 14752,
-  14876, 14910, 15004, 15048, 15218, 15277, 15308, 15362, 15374, 15400,
-  15427, 15483, 15522, 15531, 15532, 15601, 15608, 15609, 15610, 15632,
-  15640, 15670, 15672, 15680, 15681, 15723, 15734, 15735, 15736, 15748,
-  15749, 15754, 15760, 15763, 15764, 15797, 15799, 15825, 15844, 15847,
-  15849, 15855, 15856, 15857, 15859, 15867, 15886, 15887, 15890, 15892,
-  15893, 15895, 15897, 15905, 15909, 15917, 15919, 15921, 15923, 15939,
-  15948, 15963, 15966, 15985, 15988, 15997, 16032, 16034, 16036, 16037,
-  16041, 16055, 16071, 16072, 16074, 16077, 16078, 16103, 16112, 16143,
-  16144, 16146, 16150, 16151, 16153, 16167, 16172, 16214, 16245, 16271.
+  156, 387, 431, 832, 2801, 6787, 7003, 9954, 10253, 10278, 11087, 11157,
+  11214, 13028, 13982, 13985, 14029, 14032, 14143, 14155, 14547, 14699,
+  14752, 14876, 14910, 15004, 15048, 15218, 15277, 15308, 15362, 15374,
+  15400, 15427, 15483, 15522, 15531, 15532, 15601, 15608, 15609, 15610,
+  15632, 15640, 15670, 15672, 15680, 15681, 15723, 15734, 15735, 15736,
+  15748, 15749, 15754, 15760, 15763, 15764, 15797, 15799, 15825, 15844,
+  15847, 15849, 15855, 15856, 15857, 15859, 15867, 15886, 15887, 15890,
+  15892, 15893, 15895, 15897, 15905, 15909, 15917, 15919, 15921, 15923,
+  15939, 15948, 15963, 15966, 15985, 15988, 15997, 16032, 16034, 16036,
+  16037, 16041, 16055, 16071, 16072, 16074, 16077, 16078, 16103, 16112,
+  16143, 16144, 16146, 16150, 16151, 16153, 16167, 16172, 16214, 16245,
+  16271.
 
 * The public headers no longer use __unused nor __block.  This change is to
   support compiling programs that are derived from BSD sources and use
diff --git a/math/libm-test.inc b/math/libm-test.inc
index 7c599c101c..6e9d37ad22 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -8134,10 +8134,12 @@ static const struct test_f_f_data exp10_test_data[] =
     TEST_f_f (exp10, 4932, 1.0e4932L),
     TEST_f_f (exp10, -4932, 1.0e-4932L, UNDERFLOW_EXCEPTION),
 #endif
+    TEST_f_f (exp10, 1e5, plus_infty, OVERFLOW_EXCEPTION|ERRNO_ERANGE),
+    TEST_f_f (exp10, -1e5, 0, UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
     TEST_f_f (exp10, 1e6, plus_infty, OVERFLOW_EXCEPTION|ERRNO_ERANGE),
-    TEST_f_f (exp10, -1e6, 0, UNDERFLOW_EXCEPTION),
+    TEST_f_f (exp10, -1e6, 0, UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
     TEST_f_f (exp10, max_value, plus_infty, OVERFLOW_EXCEPTION|ERRNO_ERANGE),
-    TEST_f_f (exp10, -max_value, 0, UNDERFLOW_EXCEPTION),
+    TEST_f_f (exp10, -max_value, 0, UNDERFLOW_EXCEPTION|ERRNO_ERANGE),
     TEST_f_f (exp10, 0.75L, 5.62341325190349080394951039776481231L),
   };
 
diff --git a/math/w_exp10.c b/math/w_exp10.c
index 3db012d1f1..17823f57ef 100644
--- a/math/w_exp10.c
+++ b/math/w_exp10.c
@@ -28,7 +28,7 @@ double
 __exp10 (double x)
 {
   double z = __ieee754_exp10 (x);
-  if (__builtin_expect (!__finite (z), 0)
+  if (__builtin_expect (!__finite (z) || z == 0, 0)
       && __finite (x) && _LIB_VERSION != _IEEE_)
     /* exp10 overflow (46) if x > 0, underflow (47) if x < 0.  */
     return __kernel_standard (x, x, 46 + !!__signbit (x));
diff --git a/math/w_exp10f.c b/math/w_exp10f.c
index 082b34faf5..e2f9185b1e 100644
--- a/math/w_exp10f.c
+++ b/math/w_exp10f.c
@@ -28,7 +28,7 @@ float
 __exp10f (float x)
 {
   float z = __ieee754_exp10f (x);
-  if (__builtin_expect (!__finitef (z), 0)
+  if (__builtin_expect (!__finitef (z) || z == 0, 0)
       && __finitef (x) && _LIB_VERSION != _IEEE_)
     /* exp10f overflow (146) if x > 0, underflow (147) if x < 0.  */
     return __kernel_standard_f (x, x, 146 + !!__signbitf (x));
diff --git a/math/w_exp10l.c b/math/w_exp10l.c
index 10f3f81fe0..19facddee6 100644
--- a/math/w_exp10l.c
+++ b/math/w_exp10l.c
@@ -28,7 +28,7 @@ long double
 __exp10l (long double x)
 {
   long double z = __ieee754_exp10l (x);
-  if (__builtin_expect (!__finitel (z), 0)
+  if (__builtin_expect (!__finitel (z) || z == 0, 0)
       && __finitel (x) && _LIB_VERSION != _IEEE_)
     /* exp10l overflow (246) if x > 0, underflow (247) if x < 0.  */
     return __kernel_standard_l (x, x, 246 + !!__signbitl (x));