Add some tests for acos*(), asin*(), atan*(), and atan2*().

3 files changed, 504 insertions, 1 deletions

diff --git a/tools/regression/lib/msun/Makefile b/tools/regression/lib/msun/Makefile
index 3302e5b..89ccd21 100644
--- a/tools/regression/lib/msun/Makefile
+++ b/tools/regression/lib/msun/Makefile
@@ -1,7 +1,7 @@
 # $FreeBSD$
 
 TESTS=	test-csqrt test-exponential test-fenv test-fma \
-	test-fmaxmin test-ilogb test-lrint \
+	test-fmaxmin test-ilogb test-invtrig test-lrint \
 	test-lround test-nan test-next test-rem test-trig
 CFLAGS+= -O0 -lm
 
diff --git a/tools/regression/lib/msun/test-invtrig.c b/tools/regression/lib/msun/test-invtrig.c
new file mode 100644
index 0000000..0eddb97
--- /dev/null
+++ b/tools/regression/lib/msun/test-invtrig.c
@@ -0,0 +1,493 @@
+/*-
+ * Copyright (c) 2008 David Schultz <das@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * Tests for corner cases in the inverse trigonometric functions. Some
+ * accuracy tests are included as well, but these are very basic
+ * sanity checks, not intended to be comprehensive.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <assert.h>
+#include <fenv.h>
+#include <float.h>
+#include <math.h>
+#include <stdio.h>
+
+#define	ALL_STD_EXCEPT	(FE_DIVBYZERO | FE_INEXACT | FE_INVALID | \
+			 FE_OVERFLOW | FE_UNDERFLOW)
+
+#define	LEN(a)		(sizeof(a) / sizeof((a)[0]))
+
+#pragma STDC FENV_ACCESS ON
+
+/*
+ * Test that a function returns the correct value and sets the
+ * exception flags correctly. A tolerance specifying the maximum
+ * relative error allowed may be specified. For the 'testall'
+ * functions, the tolerance is specified in ulps.
+ *
+ * These are macros instead of functions so that assert provides more
+ * meaningful error messages.
+ */
+#define	test_tol(func, x, result, tol, excepts) do {			\
+	volatile long double _in = (x), _out = (result);		\
+	assert(feclearexcept(FE_ALL_EXCEPT) == 0);			\
+	assert(fpequal(func(_in), _out, (tol)));			\
+	assert((func, fetestexcept(ALL_STD_EXCEPT) == (excepts)));	\
+} while (0)
+#define test(func, x, result, excepts)					\
+	test_tol(func, (x), (result), 0, (excepts))
+
+#define	testall_tol(prefix, x, result, tol, excepts) do {		\
+	test_tol(prefix, (double)(x), (double)(result),			\
+		 (tol) * ldexp(1.0, 1 - DBL_MANT_DIG), (excepts));	\
+	test_tol(prefix##f, (float)(x), (float)(result),		\
+		 (tol) * ldexpf(1.0, 1 - FLT_MANT_DIG), (excepts));	\
+	test_tol(prefix##l, (x), (result),				\
+		 (tol) * ldexpl(1.0, 1 - LDBL_MANT_DIG), (excepts));	\
+} while (0)
+#define testall(prefix, x, result, excepts)				\
+	testall_tol(prefix, (x), (result), 0, (excepts))
+
+#define	test2_tol(func, y, x, result, tol, excepts) do {		\
+	volatile long double _iny = (y), _inx = (x), _out = (result);	\
+	assert(feclearexcept(FE_ALL_EXCEPT) == 0);			\
+	assert(fpequal(func(_iny, _inx), _out, (tol)));			\
+	assert((func, fetestexcept(ALL_STD_EXCEPT) == (excepts)));	\
+} while (0)
+#define test2(func, y, x, result, excepts)				\
+	test2_tol(func, (y), (x), (result), 0, (excepts))
+
+#define	testall2_tol(prefix, y, x, result, tol, excepts) do {		\
+	test2_tol(prefix, (double)(y), (double)(x), (double)(result),	\
+		  (tol) * ldexp(1.0, 1 - DBL_MANT_DIG), (excepts));	\
+	test2_tol(prefix##f, (float)(y), (float)(x), (float)(result),	\
+		  (tol) * ldexpf(1.0, 1 - FLT_MANT_DIG), (excepts));	\
+	test2_tol(prefix##l, (y), (x), (result),			\
+		  (tol) * ldexpl(1.0, 1 - LDBL_MANT_DIG), (excepts));	\
+} while (0)
+#define testall2(prefix, y, x, result, excepts)				\
+	testall2_tol(prefix, (y), (x), (result), 0, (excepts))
+
+long double
+pi =   3.14159265358979323846264338327950280e+00L,
+pio3 = 1.04719755119659774615421446109316766e+00L,
+c3pi = 9.42477796076937971538793014983850839e+00L,
+c5pi = 1.57079632679489661923132169163975140e+01L,
+c7pi = 2.19911485751285526692385036829565196e+01L,
+c5pio3 = 5.23598775598298873077107230546583851e+00L,
+sqrt2m1 = 4.14213562373095048801688724209698081e-01L;
+
+/*
+ * Determine whether x and y are equal to within a relative error of tol,
+ * with two special rules:
+ *	+0.0 != -0.0
+ *	 NaN == NaN
+ */
+int
+fpequal(long double x, long double y, long double tol)
+{
+	fenv_t env;
+	int ret;
+
+	if (isnan(x) && isnan(y))
+		return (1);
+	if (signbit(x) != signbit(y))
+		return (0);
+	if (x == y)
+		return (1);
+	if (tol == 0)
+		return (0);
+
+	/* Hard case: need to check the tolerance. */
+	feholdexcept(&env);
+	ret = fabsl(x - y) <= fabsl(y * tol);
+	fesetenv(&env);
+	return (ret);
+}
+
+/*
+ * Test special case inputs in asin(), acos() and atan(): signed
+ * zeroes, infinities, and NaNs.
+ */
+static void
+test_special(void)
+{
+
+	testall(asin, 0.0, 0.0, 0);
+	testall(acos, 0.0, pi / 2, FE_INEXACT);
+	testall(atan, 0.0, 0.0, 0);
+	testall(asin, -0.0, -0.0, 0);
+	testall(acos, -0.0, pi / 2, FE_INEXACT);
+	testall(atan, -0.0, -0.0, 0);
+
+	testall(asin, INFINITY, NAN, FE_INVALID);
+	testall(acos, INFINITY, NAN, FE_INVALID);
+	testall(atan, INFINITY, pi / 2, FE_INEXACT);
+	testall(asin, -INFINITY, NAN, FE_INVALID);
+	testall(acos, -INFINITY, NAN, FE_INVALID);
+	testall(atan, -INFINITY, -pi / 2, FE_INEXACT);
+
+	testall(asin, NAN, NAN, 0);
+	testall(acos, NAN, NAN, 0);
+	testall(atan, NAN, NAN, 0);
+}
+
+/*
+ * Test special case inputs in atan2(), where the exact value of y/x is
+ * zero or non-finite.
+ */
+static void
+test_special_atan2(void)
+{
+	long double z;
+	int e;
+
+	testall2(atan2, 0.0, -0.0, pi, FE_INEXACT);
+	testall2(atan2, -0.0, -0.0, -pi, FE_INEXACT);
+	testall2(atan2, 0.0, 0.0, 0.0, 0);
+	testall2(atan2, -0.0, 0.0, -0.0, 0);
+
+	testall2(atan2, INFINITY, -INFINITY, c3pi / 4, FE_INEXACT);
+	testall2(atan2, -INFINITY, -INFINITY, -c3pi / 4, FE_INEXACT);
+	testall2(atan2, INFINITY, INFINITY, pi / 4, FE_INEXACT);
+	testall2(atan2, -INFINITY, INFINITY, -pi / 4, FE_INEXACT);
+
+	/* Tests with one input in the range (0, Inf]. */
+	z = 1.23456789L;
+	for (e = FLT_MIN_EXP - FLT_MANT_DIG; e <= FLT_MAX_EXP; e++) {
+		test2(atan2f, 0.0, ldexpf(z, e), 0.0, 0);
+		test2(atan2f, -0.0, ldexpf(z, e), -0.0, 0);
+		test2(atan2f, 0.0, ldexpf(-z, e), (float)pi, FE_INEXACT);
+		test2(atan2f, -0.0, ldexpf(-z, e), (float)-pi, FE_INEXACT);
+		test2(atan2f, ldexpf(z, e), 0.0, (float)pi / 2, FE_INEXACT);
+		test2(atan2f, ldexpf(z, e), -0.0, (float)pi / 2, FE_INEXACT);
+		test2(atan2f, ldexpf(-z, e), 0.0, (float)-pi / 2, FE_INEXACT);
+		test2(atan2f, ldexpf(-z, e), -0.0, (float)-pi / 2, FE_INEXACT);
+	}
+	for (e = DBL_MIN_EXP - DBL_MANT_DIG; e <= DBL_MAX_EXP; e++) {
+		test2(atan2, 0.0, ldexp(z, e), 0.0, 0);
+		test2(atan2, -0.0, ldexp(z, e), -0.0, 0);
+		test2(atan2, 0.0, ldexp(-z, e), (double)pi, FE_INEXACT);
+		test2(atan2, -0.0, ldexp(-z, e), (double)-pi, FE_INEXACT);
+		test2(atan2, ldexp(z, e), 0.0, (double)pi / 2, FE_INEXACT);
+		test2(atan2, ldexp(z, e), -0.0, (double)pi / 2, FE_INEXACT);
+		test2(atan2, ldexp(-z, e), 0.0, (double)-pi / 2, FE_INEXACT);
+		test2(atan2, ldexp(-z, e), -0.0, (double)-pi / 2, FE_INEXACT);
+	}
+	for (e = LDBL_MIN_EXP - LDBL_MANT_DIG; e <= LDBL_MAX_EXP; e++) {
+		test2(atan2l, 0.0, ldexpl(z, e), 0.0, 0);
+		test2(atan2l, -0.0, ldexpl(z, e), -0.0, 0);
+		test2(atan2l, 0.0, ldexpl(-z, e), pi, FE_INEXACT);
+		test2(atan2l, -0.0, ldexpl(-z, e), -pi, FE_INEXACT);
+		test2(atan2l, ldexpl(z, e), 0.0, pi / 2, FE_INEXACT);
+		test2(atan2l, ldexpl(z, e), -0.0, pi / 2, FE_INEXACT);
+		test2(atan2l, ldexpl(-z, e), 0.0, -pi / 2, FE_INEXACT);
+		test2(atan2l, ldexpl(-z, e), -0.0, -pi / 2, FE_INEXACT);
+	}
+
+	/* Tests with one input in the range (0, Inf). */
+	for (e = FLT_MIN_EXP - FLT_MANT_DIG; e <= FLT_MAX_EXP - 1; e++) {
+		test2(atan2f, ldexpf(z, e), INFINITY, 0.0, 0);
+		test2(atan2f, ldexpf(-z,e), INFINITY, -0.0, 0);
+		test2(atan2f, ldexpf(z, e), -INFINITY, (float)pi, FE_INEXACT);
+		test2(atan2f, ldexpf(-z,e), -INFINITY, (float)-pi, FE_INEXACT);
+		test2(atan2f, INFINITY, ldexpf(z,e), (float)pi/2, FE_INEXACT);
+		test2(atan2f, INFINITY, ldexpf(-z,e), (float)pi/2, FE_INEXACT);
+		test2(atan2f, -INFINITY, ldexpf(z,e), (float)-pi/2,FE_INEXACT);
+		test2(atan2f, -INFINITY, ldexpf(-z,e),(float)-pi/2,FE_INEXACT);
+	}
+	for (e = DBL_MIN_EXP - DBL_MANT_DIG; e <= DBL_MAX_EXP - 1; e++) {
+		test2(atan2, ldexp(z, e), INFINITY, 0.0, 0);
+		test2(atan2, ldexp(-z,e), INFINITY, -0.0, 0);
+		test2(atan2, ldexp(z, e), -INFINITY, (double)pi, FE_INEXACT);
+		test2(atan2, ldexp(-z,e), -INFINITY, (double)-pi, FE_INEXACT);
+		test2(atan2, INFINITY, ldexp(z,e), (double)pi/2, FE_INEXACT);
+		test2(atan2, INFINITY, ldexp(-z,e), (double)pi/2, FE_INEXACT);
+		test2(atan2, -INFINITY, ldexp(z,e), (double)-pi/2,FE_INEXACT);
+		test2(atan2, -INFINITY, ldexp(-z,e),(double)-pi/2,FE_INEXACT);
+	}
+	for (e = LDBL_MIN_EXP - LDBL_MANT_DIG; e <= LDBL_MAX_EXP - 1; e++) {
+		test2(atan2l, ldexpl(z, e), INFINITY, 0.0, 0);
+		test2(atan2l, ldexpl(-z,e), INFINITY, -0.0, 0);
+		test2(atan2l, ldexpl(z, e), -INFINITY, pi, FE_INEXACT);
+		test2(atan2l, ldexpl(-z,e), -INFINITY, -pi, FE_INEXACT);
+		test2(atan2l, INFINITY, ldexpl(z, e), pi / 2, FE_INEXACT);
+		test2(atan2l, INFINITY, ldexpl(-z, e), pi / 2, FE_INEXACT);
+		test2(atan2l, -INFINITY, ldexpl(z, e), -pi / 2, FE_INEXACT);
+		test2(atan2l, -INFINITY, ldexpl(-z, e), -pi / 2, FE_INEXACT);
+	}
+}
+
+/*
+ * Test various inputs to asin(), acos() and atan() and verify that the
+ * results are accurate to within 1 ulp.
+ */
+static void
+test_accuracy(void)
+{
+
+	/* We expect correctly rounded results for these basic cases. */
+	testall(asin, 1.0, pi / 2, FE_INEXACT);
+	testall(acos, 1.0, 0, 0);
+	testall(atan, 1.0, pi / 4, FE_INEXACT);
+	testall(asin, -1.0, -pi / 2, FE_INEXACT);
+	testall(acos, -1.0, pi, FE_INEXACT);
+	testall(atan, -1.0, -pi / 4, FE_INEXACT);
+
+	/*
+	 * Here we expect answers to be within 1 ulp, although inexactness
+	 * in the input, combined with double rounding, could cause larger
+	 * errors.
+	 */
+
+	testall_tol(asin, sqrtl(2) / 2, pi / 4, 1, FE_INEXACT);
+	testall_tol(acos, sqrtl(2) / 2, pi / 4, 1, FE_INEXACT);
+	testall_tol(asin, -sqrtl(2) / 2, -pi / 4, 1, FE_INEXACT);
+	testall_tol(acos, -sqrtl(2) / 2, c3pi / 4, 1, FE_INEXACT);
+
+	testall_tol(asin, sqrtl(3) / 2, pio3, 1, FE_INEXACT);
+	testall_tol(acos, sqrtl(3) / 2, pio3 / 2, 1, FE_INEXACT);
+	testall_tol(atan, sqrtl(3), pio3, 1, FE_INEXACT);
+	testall_tol(asin, -sqrtl(3) / 2, -pio3, 1, FE_INEXACT);
+	testall_tol(acos, -sqrtl(3) / 2, c5pio3 / 2, 1, FE_INEXACT);
+	testall_tol(atan, -sqrtl(3), -pio3, 1, FE_INEXACT);
+
+	testall_tol(atan, sqrt2m1, pi / 8, 1, FE_INEXACT);
+	testall_tol(atan, -sqrt2m1, -pi / 8, 1, FE_INEXACT);
+}
+
+/*
+ * Test inputs to atan2() where x is a power of 2. These are easy cases
+ * because y/x is exact.
+ */
+static void
+test_p2x_atan2(void)
+{
+
+	testall2(atan2, 1.0, 1.0, pi / 4, FE_INEXACT);
+	testall2(atan2, 1.0, -1.0, c3pi / 4, FE_INEXACT);
+	testall2(atan2, -1.0, 1.0, -pi / 4, FE_INEXACT);
+	testall2(atan2, -1.0, -1.0, -c3pi / 4, FE_INEXACT);
+
+	testall2_tol(atan2, sqrt2m1 * 2, 2.0, pi / 8, 1, FE_INEXACT);
+	testall2_tol(atan2, sqrt2m1 * 2, -2.0, c7pi / 8, 1, FE_INEXACT);
+	testall2_tol(atan2, -sqrt2m1 * 2, 2.0, -pi / 8, 1, FE_INEXACT);
+	testall2_tol(atan2, -sqrt2m1 * 2, -2.0, -c7pi / 8, 1, FE_INEXACT);
+
+	testall2_tol(atan2, sqrtl(3) * 0.5, 0.5, pio3, 1, FE_INEXACT);
+	testall2_tol(atan2, sqrtl(3) * 0.5, -0.5, pio3 * 2, 1, FE_INEXACT);
+	testall2_tol(atan2, -sqrtl(3) * 0.5, 0.5, -pio3, 1, FE_INEXACT);
+	testall2_tol(atan2, -sqrtl(3) * 0.5, -0.5, -pio3 * 2, 1, FE_INEXACT);
+}
+
+/*
+ * Test inputs very close to 0.
+ */
+static void
+test_tiny(void)
+{
+	float tiny = 0x1.23456p-120f;
+
+	testall(asin, tiny, tiny, FE_INEXACT);
+	testall(acos, tiny, pi / 2, FE_INEXACT);
+	testall(atan, tiny, tiny, FE_INEXACT);
+
+	testall(asin, -tiny, -tiny, FE_INEXACT);
+	testall(acos, -tiny, pi / 2, FE_INEXACT);
+	testall(atan, -tiny, -tiny, FE_INEXACT);
+
+	/* Test inputs to atan2() that would cause y/x to underflow. */
+	test2(atan2f, 0x1.0p-100, 0x1.0p100, 0.0, FE_INEXACT | FE_UNDERFLOW);
+	test2(atan2, 0x1.0p-1000, 0x1.0p1000, 0.0, FE_INEXACT | FE_UNDERFLOW);
+	test2(atan2l, ldexpl(1.0, 100 - LDBL_MAX_EXP),
+	      ldexpl(1.0, LDBL_MAX_EXP - 100), 0.0, FE_INEXACT | FE_UNDERFLOW);
+	test2(atan2f, -0x1.0p-100, 0x1.0p100, -0.0, FE_INEXACT | FE_UNDERFLOW);
+	test2(atan2, -0x1.0p-1000, 0x1.0p1000, -0.0, FE_INEXACT | FE_UNDERFLOW);
+	test2(atan2l, -ldexpl(1.0, 100 - LDBL_MAX_EXP),
+	      ldexpl(1.0, LDBL_MAX_EXP - 100), -0.0, FE_INEXACT | FE_UNDERFLOW);
+	test2(atan2f, 0x1.0p-100, -0x1.0p100, (float)pi, FE_INEXACT);
+	test2(atan2, 0x1.0p-1000, -0x1.0p1000, (double)pi, FE_INEXACT);
+	test2(atan2l, ldexpl(1.0, 100 - LDBL_MAX_EXP),
+	      -ldexpl(1.0, LDBL_MAX_EXP - 100), pi, FE_INEXACT);
+	test2(atan2f, -0x1.0p-100, -0x1.0p100, (float)-pi, FE_INEXACT);
+	test2(atan2, -0x1.0p-1000, -0x1.0p1000, (double)-pi, FE_INEXACT);
+	test2(atan2l, -ldexpl(1.0, 100 - LDBL_MAX_EXP),
+	      -ldexpl(1.0, LDBL_MAX_EXP - 100), -pi, FE_INEXACT);
+}
+
+/*
+ * Test very large inputs to atan().
+ */
+static void
+test_atan_huge(void)
+{
+	float huge = 0x1.23456p120;
+
+	testall(atan, huge, pi / 2, FE_INEXACT);
+	testall(atan, -huge, -pi / 2, FE_INEXACT);
+
+	/* Test inputs to atan2() that would cause y/x to overflow. */
+	test2(atan2f, 0x1.0p100, 0x1.0p-100, (float)pi / 2, FE_INEXACT);
+	test2(atan2, 0x1.0p1000, 0x1.0p-1000, (double)pi / 2, FE_INEXACT);
+	test2(atan2l, ldexpl(1.0, LDBL_MAX_EXP - 100),
+	      ldexpl(1.0, 100 - LDBL_MAX_EXP), pi / 2, FE_INEXACT);
+	test2(atan2f, -0x1.0p100, 0x1.0p-100, (float)-pi / 2, FE_INEXACT);
+	test2(atan2, -0x1.0p1000, 0x1.0p-1000, (double)-pi / 2, FE_INEXACT);
+	test2(atan2l, -ldexpl(1.0, LDBL_MAX_EXP - 100),
+	      ldexpl(1.0, 100 - LDBL_MAX_EXP), -pi / 2, FE_INEXACT);
+	/*
+	 * XXX We ought to be able to insist that these are correctly rounded,
+	 *     but that isn't true in practice.
+	 */
+	test2_tol(atan2f, 0x1.0p100, -0x1.0p-100, (float)pi / 2,
+		  1, FE_INEXACT);
+	test2_tol(atan2, 0x1.0p1000, -0x1.0p-1000, (double)pi / 2,
+		  1, FE_INEXACT);
+	test2_tol(atan2l, ldexpl(1.0, LDBL_MAX_EXP - 100),
+		  -ldexpl(1.0, 100 - LDBL_MAX_EXP), pi / 2, 0, FE_INEXACT);
+	test2_tol(atan2f, -0x1.0p100, -0x1.0p-100, (float)-pi / 2,
+		  1, FE_INEXACT);
+	test2_tol(atan2, -0x1.0p1000, -0x1.0p-1000, (double)-pi / 2,
+		  1, FE_INEXACT);
+	test2_tol(atan2l, -ldexpl(1.0, LDBL_MAX_EXP - 100),
+		  -ldexpl(1.0, 100 - LDBL_MAX_EXP), -pi / 2, 1, FE_INEXACT);
+}
+
+/*
+ * Test that sin(asin(x)) == x, and similarly for acos() and atan().
+ * You need to have a working sinl(), cosl(), and tanl() for these
+ * tests to pass.
+ */
+static long double
+sinasinf(float x)
+{
+
+	return (sinl(asinf(x)));
+}
+
+static long double
+sinasin(double x)
+{
+
+	return (sinl(asin(x)));
+}
+
+static long double
+sinasinl(long double x)
+{
+
+	return (sinl(asinl(x)));
+}
+
+static long double
+cosacosf(float x)
+{
+
+	return (cosl(acosf(x)));
+}
+
+static long double
+cosacos(double x)
+{
+
+	return (cosl(acos(x)));
+}
+
+static long double
+cosacosl(long double x)
+{
+
+	return (cosl(acosl(x)));
+}
+
+static long double
+tanatanf(float x)
+{
+
+	return (tanl(atanf(x)));
+}
+
+static long double
+tanatan(double x)
+{
+
+	return (tanl(atan(x)));
+}
+
+static long double
+tanatanl(long double x)
+{
+
+	return (tanl(atanl(x)));
+}
+
+static void
+test_inverse(void)
+{
+	float i;
+
+	for (i = -1; i <= 1; i += 0x1.0p-12f) {
+		testall_tol(sinasin, i, i, 2, i == 0 ? 0 : FE_INEXACT);
+		/* The relative error for cosacos is very large near x=0. */
+		if (fabsf(i) > 0x1.0p-4f)
+			testall_tol(cosacos, i, i, 16, i == 1 ? 0 : FE_INEXACT);
+		testall_tol(tanatan, i, i, 2, i == 0 ? 0 : FE_INEXACT);
+	}
+}
+
+int
+main(int argc, char *argv[])
+{
+
+	printf("1..7\n");
+
+	test_special();
+	printf("ok 1 - special\n");
+
+	test_special_atan2();
+	printf("ok 2 - atan2 special\n");
+
+	test_accuracy();
+	printf("ok 3 - accuracy\n");
+
+	test_p2x_atan2();
+	printf("ok 4 - atan2 p2x\n");
+
+	test_tiny();
+	printf("ok 5 - tiny inputs\n");
+
+	test_atan_huge();
+	printf("ok 6 - atan huge inputs\n");
+
+	test_inverse();
+	printf("ok 7 - inverse\n");
+
+	return (0);
+}
diff --git a/tools/regression/lib/msun/test-invtrig.t b/tools/regression/lib/msun/test-invtrig.t
new file mode 100644
index 0000000..8bdfd03
--- /dev/null
+++ b/tools/regression/lib/msun/test-invtrig.t
@@ -0,0 +1,10 @@
+#!/bin/sh
+# $FreeBSD$
+
+cd `dirname $0`
+
+executable=`basename $0 .t`
+
+make $executable 2>&1 > /dev/null
+
+exec ./$executable