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Fix csin, csinh overflow in directed rounding modes (bug 18593) [committed]
- From: Joseph Myers <joseph at codesourcery dot com>
- To: <libc-alpha at sourceware dot org>
- Date: Wed, 24 Jun 2015 16:21:33 +0000
- Subject: Fix csin, csinh overflow in directed rounding modes (bug 18593) [committed]
- Authentication-results: sourceware.org; auth=none
csin and csinh can produce bad results when overflowing in directed
rounding modes, because a multiplication that can overflow is followed
by a possible negation. This patch fixes this by negating one of the
arguments of the multiplication before the multiplication instead of
negating the result.
The new tests for this issue are added to auto-libm-test-in, starting
use of that file for csin and csinh. The issue was found in the
course of moving existing tests for csin and csinh (existing tests, by
being enabled in more cases than previously, showed the issue for
float and double but not for long double); that move will now be done
separately.
Tested for x86_64 and x86 and ulps updated accordingly. Committed.
(auto-libm-test-out diffs omitted below.)
2015-06-24 Joseph Myers <joseph@codesourcery.com>
[BZ #18593]
* math/s_csin.c (__csin): Negate before rather than after possibly
overflowing multiplication.
* math/s_csinf.c (__csinf): Likewise.
* math/s_csinh.c (__csinh): Likewise.
* math/s_csinhf.c (__csinhf): Likewise.
* math/s_csinhl.c (__csinhl): Likewise.
* math/s_csinl.c (__csinl): Likewise.
* math/auto-libm-test-in: Add some tests of csin and csinh.
* math/auto-libm-test-out: Regenerated.
* math/libm-test.inc (csin_test_data): Use AUTO_TESTS_c_c.
(csinh_test_data): Likewise.
* sysdeps/x86_64/fpu/libm-test-ulps: Update.
diff --git a/math/auto-libm-test-in b/math/auto-libm-test-in
index 6545583..2389c05 100644
--- a/math/auto-libm-test-in
+++ b/math/auto-libm-test-in
@@ -955,6 +955,16 @@ cpow 0.75 1.25 1.0 1.0 xfail-rounding
cpow 0.75 1.25 1.0 0.0
cpow 0.75 1.25 0.0 1.0
+csin 0.75 1e6
+csin 0.75 -1e6
+csin -0.75 1e6
+csin -0.75 -1e6
+
+csinh 1e6 0.75
+csinh -1e6 0.75
+csinh 1e6 -0.75
+csinh -1e6 -0.75
+
csqrt 0 0
csqrt 0 -0
csqrt -0 0
diff --git a/math/libm-test.inc b/math/libm-test.inc
index 03c3831..ba8e8ff 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -6466,6 +6466,8 @@ static const struct test_c_c_data csin_test_data[] =
TEST_c_c (csin, 0x1p-16434L, 22730, 1.217853148905605987081057582351152052687e4924L, plus_oflow, OVERFLOW_EXCEPTION),
#endif
+ AUTO_TESTS_c_c (csin),
+
TEST_c_c (csin, min_subnorm_value, min_value, min_subnorm_value, min_value, UNDERFLOW_EXCEPTION),
TEST_c_c (csin, min_value, min_subnorm_value, min_value, min_subnorm_value, UNDERFLOW_EXCEPTION),
};
@@ -6563,6 +6565,8 @@ static const struct test_c_c_data csinh_test_data[] =
TEST_c_c (csinh, 22730, 0x1p-16434L, plus_oflow, 1.217853148905605987081057582351152052687e4924L, OVERFLOW_EXCEPTION),
#endif
+ AUTO_TESTS_c_c (csinh),
+
TEST_c_c (csinh, min_subnorm_value, min_value, min_subnorm_value, min_value, UNDERFLOW_EXCEPTION),
TEST_c_c (csinh, min_value, min_subnorm_value, min_value, min_subnorm_value, UNDERFLOW_EXCEPTION),
};
diff --git a/math/s_csin.c b/math/s_csin.c
index f1ddb4e..ceee25f 100644
--- a/math/s_csin.c
+++ b/math/s_csin.c
@@ -52,6 +52,9 @@ __csin (__complex__ double x)
cosix = 1.0;
}
+ if (negate)
+ sinix = -sinix;
+
if (fabs (__imag__ x) > t)
{
double exp_t = __ieee754_exp (t);
@@ -86,9 +89,6 @@ __csin (__complex__ double x)
__imag__ retval = __ieee754_sinh (__imag__ x) * cosix;
}
- if (negate)
- __real__ retval = -__real__ retval;
-
if (fabs (__real__ retval) < DBL_MIN)
{
volatile double force_underflow
diff --git a/math/s_csinf.c b/math/s_csinf.c
index 6c68189..daca689 100644
--- a/math/s_csinf.c
+++ b/math/s_csinf.c
@@ -52,6 +52,9 @@ __csinf (__complex__ float x)
cosix = 1.0f;
}
+ if (negate)
+ sinix = -sinix;
+
if (fabsf (__imag__ x) > t)
{
float exp_t = __ieee754_expf (t);
@@ -86,9 +89,6 @@ __csinf (__complex__ float x)
__imag__ retval = __ieee754_sinhf (__imag__ x) * cosix;
}
- if (negate)
- __real__ retval = -__real__ retval;
-
if (fabsf (__real__ retval) < FLT_MIN)
{
volatile float force_underflow
diff --git a/math/s_csinh.c b/math/s_csinh.c
index c607c2a..d940c97 100644
--- a/math/s_csinh.c
+++ b/math/s_csinh.c
@@ -52,6 +52,9 @@ __csinh (__complex__ double x)
cosix = 1.0;
}
+ if (negate)
+ cosix = -cosix;
+
if (fabs (__real__ x) > t)
{
double exp_t = __ieee754_exp (t);
@@ -86,9 +89,6 @@ __csinh (__complex__ double x)
__imag__ retval = __ieee754_cosh (__real__ x) * sinix;
}
- if (negate)
- __real__ retval = -__real__ retval;
-
if (fabs (__real__ retval) < DBL_MIN)
{
volatile double force_underflow
diff --git a/math/s_csinhf.c b/math/s_csinhf.c
index 848f5d1..4e0bc03 100644
--- a/math/s_csinhf.c
+++ b/math/s_csinhf.c
@@ -52,6 +52,9 @@ __csinhf (__complex__ float x)
cosix = 1.0f;
}
+ if (negate)
+ cosix = -cosix;
+
if (fabsf (__real__ x) > t)
{
float exp_t = __ieee754_expf (t);
@@ -86,9 +89,6 @@ __csinhf (__complex__ float x)
__imag__ retval = __ieee754_coshf (__real__ x) * sinix;
}
- if (negate)
- __real__ retval = -__real__ retval;
-
if (fabsf (__real__ retval) < FLT_MIN)
{
volatile float force_underflow
diff --git a/math/s_csinhl.c b/math/s_csinhl.c
index a437d16..eeb2212 100644
--- a/math/s_csinhl.c
+++ b/math/s_csinhl.c
@@ -52,6 +52,9 @@ __csinhl (__complex__ long double x)
cosix = 1.0;
}
+ if (negate)
+ cosix = -cosix;
+
if (fabsl (__real__ x) > t)
{
long double exp_t = __ieee754_expl (t);
@@ -86,9 +89,6 @@ __csinhl (__complex__ long double x)
__imag__ retval = __ieee754_coshl (__real__ x) * sinix;
}
- if (negate)
- __real__ retval = -__real__ retval;
-
if (fabsl (__real__ retval) < LDBL_MIN)
{
volatile long double force_underflow
diff --git a/math/s_csinl.c b/math/s_csinl.c
index accaeb5..a4b1eb5 100644
--- a/math/s_csinl.c
+++ b/math/s_csinl.c
@@ -52,6 +52,9 @@ __csinl (__complex__ long double x)
cosix = 1.0;
}
+ if (negate)
+ sinix = -sinix;
+
if (fabsl (__imag__ x) > t)
{
long double exp_t = __ieee754_expl (t);
@@ -86,9 +89,6 @@ __csinl (__complex__ long double x)
__imag__ retval = __ieee754_sinhl (__imag__ x) * cosix;
}
- if (negate)
- __real__ retval = -__real__ retval;
-
if (fabsl (__real__ retval) < LDBL_MIN)
{
volatile long double force_underflow
diff --git a/sysdeps/x86_64/fpu/libm-test-ulps b/sysdeps/x86_64/fpu/libm-test-ulps
index 2e2722d..101831f 100644
--- a/sysdeps/x86_64/fpu/libm-test-ulps
+++ b/sysdeps/x86_64/fpu/libm-test-ulps
@@ -1120,9 +1120,9 @@ ildouble: 3
ldouble: 3
Function: Real part of "csin_upward":
-double: 1
+double: 2
float: 3
-idouble: 1
+idouble: 2
ifloat: 3
ildouble: 3
ldouble: 3
@@ -1148,9 +1148,9 @@ idouble: 1
ifloat: 1
Function: Real part of "csinh_downward":
-double: 1
+double: 2
float: 2
-idouble: 1
+idouble: 2
ifloat: 2
ildouble: 3
ldouble: 3
--
Joseph S. Myers
joseph@codesourcery.com