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Re: [PATCH] math/libm-test.inc: Fix cos and sincos tests against zero.


On 04/10/2013 03:46 AM, Andreas Jaeger wrote:
> So, you need to fix this also for each long double variant as Andreas 
> Schwab and you discussed elsewhere.
> 
>> Is this the right way forward, even if it is logically the correct
>> answer? I would say yes. I would say the test suite as it is right
>> now is testing against the "naive" expected result. It works because
>> ulp(0) for the testsuite is a huge value that allows all sorts of
>> inaccurate zero values.
>>
>> Comments?
> 
> Thanks a lot for digging into this, I agree with your analysis and think 
> this is fine,

I think that's all the formats for all the targets.

* 32-bit float (flt-32) [*]
* 64-bit double (dbl-64) [*]
* 64-bit long double (some aliases) [hppa]
* 96-bit long double (ldbl-96) [m68k, ia64, x86, x86-64, x32]
* 128-bit IBM long double (ldbl-128ibm) [power]
* 128-bit long double (ldbl-128) [mips64, alpha, aarch64, s390, s390x, sparc32, sparc64]

v2
- Add support for double == long double.
- Add support for 128-bit IMB long double.
- Add support for IEEE 128-bit long double.

No regressions on x86-64 or i686, the others were added blindly
with the help of machine maintainers. Should be OK.

OK?

2013-04-09  Carlos O'Donell <carlos@redhat.com>

	* math/libm-test.inc (cos_test): Fix PI/2 test.
	(sincos_test): Likewise.
	* sysdeps/x86_64/fpu/libm-test-ulps: Regenerate.
	* sysdeps/i386/fpu/libm-test-ulps: Regenerate.

diff --git a/math/libm-test.inc b/math/libm-test.inc
index 78d2107..0049fcd 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -5330,7 +5330,31 @@ cos_test (void)
 
   TEST_f_f (cos, M_PI_6l * 2.0, 0.5);
   TEST_f_f (cos, M_PI_6l * 4.0, -0.5);
-  TEST_f_f (cos, M_PI_2l, 0);
+
+  /* The value of M_PI_2l is never exactly PI/2, and therefore the
+     answer is never exactly zero. The answer is equal to the error
+     in rounding PI/2 for the type used.  Thus the answer is unique
+     to each type.  */
+#ifdef TEST_FLOAT
+  /* 32-bit float.  */
+  TEST_f_f (cos, M_PI_2l, -4.371139000186241438857289400265215e-8L);
+#endif
+#if defined TEST_DOUBLE || (defined TEST_LDOUBLE && LDBL_MANT_DIG == 53)
+  /* 64-bit double or 64-bit long double.  */
+  TEST_f_f (cos, M_PI_2l, 6.123233995736765886130329661375001e-17L);
+#endif
+#if defined TEST_LDOUBLE && LDBL_MANT_DIG == 64
+  /* 96-bit long double.  */
+  TEST_f_f (cos, M_PI_2l, -2.50827880633416601177866354016537e-20L);
+#endif
+#if defined TEST_LDOUBLE && LDBL_MANT_DIG == 106
+  /* 128-bit IBM long double.  */
+  TEST_f_f (cos, M_PI_2l, 1.082856673921913968223746169860580e-32L);
+#endif
+#if defined TEST_LDOUBLE && LDBL_MANT_DIG == 113
+  /* 128-bit long double.  */
+  TEST_f_f (cos, M_PI_2l, 4.335905065061890512398522013021675e-35L);
+#endif
 
   TEST_f_f (cos, 0.75L, 0.731688868873820886311838753000084544L);
 
@@ -12134,7 +12158,31 @@ sincos_test (void)
   TEST_extra (sincos, minus_infty, qnan_value, qnan_value, INVALID_EXCEPTION);
   TEST_extra (sincos, qnan_value, qnan_value, qnan_value);
 
-  TEST_extra (sincos, M_PI_2l, 1, 0);
+  /* The value of M_PI_2l is never exactly PI/2, and therefore the
+     answer is never exactly zero. The answer is equal to the error
+     in rounding PI/2 for the type used.  Thus the answer is unique
+     to each type.  */
+#ifdef TEST_FLOAT
+  /* 32-bit float.  */
+  TEST_extra (sincos, M_PI_2l, 1, -4.371139000186241438857289400265215e-8L);
+#endif
+#if defined TEST_DOUBLE || (defined TEST_LDOUBLE && LDBL_MANT_DIG == 53)
+  /* 64-bit double or 64-bit long double.  */
+  TEST_extra (sincos, M_PI_2l, 1, 6.123233995736765886130329661375001e-17L);
+#endif
+#if defined TEST_LDOUBLE && LDBL_MANT_DIG == 64
+  /* 96-bit long double.  */
+  TEST_extra (sincos, M_PI_2l, 1, -2.50827880633416601177866354016537e-20L);
+#endif
+#if defined TEST_LDOUBLE && LDBL_MANT_DIG == 106
+  /* 128-bit IBM long double.  */
+  TEST_extra (sincos, M_PI_2l, 1, 1.082856673921913968223746169860580e-32L);
+#endif
+#if defined TEST_LDOUBLE && LDBL_MANT_DIG == 113
+  /* 128-bit long double.  */
+  TEST_extra (sincos, M_PI_2l, 1, 4.335905065061890512398522013021675e-35L);
+#endif
+
   TEST_extra (sincos, M_PI_6l, 0.5, 0.86602540378443864676372317075293616L);
   TEST_extra (sincos, M_PI_6l*2.0, 0.86602540378443864676372317075293616L, 0.5);
   TEST_extra (sincos, 0.75L, 0.681638760023334166733241952779893935L, 0.731688868873820886311838753000084544L);
diff --git a/sysdeps/i386/fpu/libm-test-ulps b/sysdeps/i386/fpu/libm-test-ulps
index 4de455c..fecaa94 100644
--- a/sysdeps/i386/fpu/libm-test-ulps
+++ b/sysdeps/i386/fpu/libm-test-ulps
@@ -4149,13 +4149,6 @@ idouble: 2
 ifloat: 1
 ildouble: 1
 ldouble: 1
-Test "cos (pi/2) == 0":
-double: 1
-float: 1
-idouble: 1
-ifloat: 1
-ildouble: 1
-ldouble: 1
 
 # cos_downward
 Test "cos_downward (1) == 0.5403023058681397174009366074429766037323":
@@ -5513,13 +5506,6 @@ idouble: 1
 ifloat: 1
 ildouble: 1
 ldouble: 1
-Test "sincos (pi/2, &sin_res, &cos_res) puts 0 in cos_res":
-double: 1
-float: 1
-idouble: 1
-ifloat: 1
-ildouble: 1
-ldouble: 1
 
 # sinh
 Test "sinh (0.75) == 0.822316731935829980703661634446913849":
diff --git a/sysdeps/x86_64/fpu/libm-test-ulps b/sysdeps/x86_64/fpu/libm-test-ulps
index 28f4bfc..9c9c473 100644
--- a/sysdeps/x86_64/fpu/libm-test-ulps
+++ b/sysdeps/x86_64/fpu/libm-test-ulps
@@ -4717,13 +4717,6 @@ idouble: 2
 ifloat: 1
 ildouble: 1
 ldouble: 1
-Test "cos (pi/2) == 0":
-double: 1
-float: 1
-idouble: 1
-ifloat: 1
-ildouble: 1
-ldouble: 1
 
 # cos_downward
 Test "cos_downward (1) == 0.5403023058681397174009366074429766037323":
@@ -5984,13 +5977,6 @@ idouble: 1
 ifloat: 1
 ildouble: 1
 ldouble: 1
-Test "sincos (pi/2, &sin_res, &cos_res) puts 0 in cos_res":
-double: 1
-float: 1
-idouble: 1
-ifloat: 1
-ildouble: 1
-ldouble: 1
 Test "sincos (pi/6, &sin_res, &cos_res) puts 0.86602540378443864676372317075293616 in cos_res":
 float: 1
 ifloat: 1
---

Cheers,
Carlos.


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