Add iscanonical.

TS 18661-1 adds an iscanonical classification macro to <math.h>.

The motivation for this is decimal floating-point, where some values
have both canonical and noncanonical encodings.  For IEEE binary
interchange formats, all encodings are canonical.  For x86/m68k
ldbl-96, and for ldbl-128ibm, there are encodings that do not
represent any valid value of the type; although formally iscanonical
does not need to handle trap representations (and so could just always
return 1), it seems useful, and in line with the description in the TS
of "representations that are extraneous to the floating-point model"
as being non-canonical (as well as "redundant representations of some
or all of its values"), for it to detect those representations and
return 0 for them.

This patch adds iscanonical to glibc.  It goes in a header
<bits/iscanonical.h>, included under appropriate conditions in
<math.h>.  The default header version just evaluates the argument
(converted to its semantic type, though current GCC will probably
discard that conversion and any exceptions resulting from it) and
returns 1.  ldbl-96 and ldbl-128ibm then have versions of the header
that call a function __iscanonicall for long double (the sizeof-based
tests will of course need updating for float128 support, like other
such type-generic macro implementations).  The ldbl-96 version of
__iscanonicall has appropriate conditionals to reflect the differences
in the m68k version of that format (where the high mantissa bit may be
either 0 or 1 when the exponent is 0 or 0x7fff).  Corresponding tests
for those formats are added as well.  Other architectures do not have
any new functions added because just returning 1 is correct for all
their floating-point formats.

Tested for x86_64, x86, mips64 (to test the default macro version) and
powerpc.

	* math/math.h [__GLIBC_USE (IEC_60559_BFP_EXT)]: Include
	<bits/iscanonical.h>.
	* bits/iscanonical.h: New file.
	* math/s_iscanonicall.c: Likewise.
	* math/Versions (__iscanonicall): New libm symbol at version
	GLIBC_2.25.
	* math/libm-test.inc (iscanonical_test_data): New array.
	(iscanonical_test): New function.
	(main): Call iscanonical_test.
	* math/Makefile (headers): Add bits/iscanonical.h.
	(type-ldouble-routines): Add s_iscanonicall.
	* manual/arith.texi (Floating Point Classes): Document
	iscanonical.
	* manual/libm-err-tab.pl: Update comment on interfaces without
	ulps tabulated.
	* sysdeps/ieee754/ldbl-128ibm/bits/iscanonical.h: New file.
	* sysdeps/ieee754/ldbl-128ibm/s_iscanonicall.c: Likewise.
	* sysdeps/ieee754/ldbl-128ibm/test-iscanonical-ldbl-128ibm.c:
	Likewise.
	* sysdeps/ieee754/ldbl-128ibm/Makefile (tests): Add
	test-iscanonical-ldbl-128ibm.
	* sysdeps/ieee754/ldbl-96/bits/iscanonical.h: New file.
	* sysdeps/ieee754/ldbl-96/s_iscanonicall.c: Likewise.
	* sysdeps/ieee754/ldbl-96/test-iscanonical-ldbl-96.c: Likewise.
	* sysdeps/ieee754/ldbl-96/Makefile: Likewise.
	* sysdeps/unix/sysv/linux/i386/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/ia64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/fpu/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc32/nofpu/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm-le.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/powerpc/powerpc64/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Likewise.

5 files changed, 35 insertions, 5 deletions

diff --git a/math/Makefile b/math/Makefile
index 7ccd59a..d2b4fd1 100644
--- a/math/Makefile
+++ b/math/Makefile
@@ -27,7 +27,7 @@ headers		:= math.h bits/mathcalls.h bits/mathinline.h bits/huge_val.h \
 		   fpu_control.h complex.h bits/cmathcalls.h fenv.h \
 		   bits/fenv.h bits/fenvinline.h bits/mathdef.h tgmath.h \
 		   bits/math-finite.h bits/math-vector.h \
-		   bits/libm-simd-decl-stubs.h
+		   bits/libm-simd-decl-stubs.h bits/iscanonical.h
 
 # FPU support code.
 aux		:= setfpucw fpu_control
@@ -94,7 +94,7 @@ types = $(type-ldouble-$(long-double-fcts)) double float
 
 # long double support
 type-ldouble-suffix := l
-type-ldouble-routines := t_sincosl k_sincosl
+type-ldouble-routines := t_sincosl k_sincosl s_iscanonicall
 type-ldouble-yes := ldouble
 
 # double support
diff --git a/math/Versions b/math/Versions
index a429221..f702051 100644
--- a/math/Versions
+++ b/math/Versions
@@ -216,5 +216,6 @@ libm {
   }
   GLIBC_2.25 {
     fesetexcept; fetestexceptflag; fegetmode; fesetmode;
+    __iscanonicall;
   }
 }
diff --git a/math/libm-test.inc b/math/libm-test.inc
index 872bafd..cbc7226 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -46,9 +46,9 @@
    cbrt, ceil, copysign, cos, cosh, drem, erf, erfc, exp, exp10, exp2, expm1,
    fabs, fdim, finite, floor, fma, fmax, fmin, fmod, fpclassify,
    frexp, gamma, hypot,
-   ilogb, isfinite, isinf, isnan, isnormal, issignaling, issubnormal, iszero,
-   isless, islessequal, isgreater, isgreaterequal, islessgreater, isunordered,
-   j0, j1, jn,
+   ilogb, iscanonical, isfinite, isinf, isnan, isnormal, issignaling,
+   issubnormal, iszero, isless, islessequal, isgreater,
+   isgreaterequal, islessgreater, isunordered, j0, j1, jn,
    ldexp, lgamma, log, log10, log1p, log2, logb,
    modf, nearbyint, nextafter, nexttoward,
    pow, pow10, remainder, remquo, rint, lrint, llrint,
@@ -8160,6 +8160,31 @@ ilogb_test (void)
   ALL_RM_TEST (ilogb, 1, ilogb_test_data, RUN_TEST_LOOP_f_i, END);
 }
 
+static const struct test_f_i_data iscanonical_test_data[] =
+  {
+    TEST_f_b (iscanonical, 0, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_b (iscanonical, minus_zero, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_b (iscanonical, 10, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_b (iscanonical, min_subnorm_value, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_b (iscanonical, -min_subnorm_value, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_b (iscanonical, min_value, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_b (iscanonical, -min_value, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_b (iscanonical, max_value, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_b (iscanonical, -max_value, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_b (iscanonical, plus_infty, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_b (iscanonical, minus_infty, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_b (iscanonical, qnan_value, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_b (iscanonical, -qnan_value, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_b (iscanonical, snan_value, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_b (iscanonical, -snan_value, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+  };
+
+static void
+iscanonical_test (void)
+{
+  ALL_RM_TEST (iscanonical, 1, iscanonical_test_data, RUN_TEST_LOOP_f_b_tg, END);
+}
+
 static const struct test_f_i_data isfinite_test_data[] =
   {
     TEST_f_b (isfinite, 0, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
@@ -12713,6 +12738,7 @@ main (int argc, char **argv)
   /* Classification macros:  */
   finite_test ();
   fpclassify_test ();
+  iscanonical_test ();
   isfinite_test ();
   isinf_test ();
   isnan_test ();
diff --git a/math/math.h b/math/math.h
index 1382baa..8cd6416 100644
--- a/math/math.h
+++ b/math/math.h
@@ -317,6 +317,8 @@ enum
 #endif /* Use ISO C99.  */
 
 #if __GLIBC_USE (IEC_60559_BFP_EXT)
+# include <bits/iscanonical.h>
+
 /* Return nonzero value if X is a signaling NaN.  */
 # ifdef __NO_LONG_DOUBLE_MATH
 #  define issignaling(x) \
diff --git a/math/s_iscanonicall.c b/math/s_iscanonicall.c
new file mode 100644
index 0000000..b5fd996
--- /dev/null
+++ b/math/s_iscanonicall.c
@@ -0,0 +1 @@
+/* Not needed by default.  */