Add llogb, llogbf, llogbl.

TS 18661-1 defines llogb functions that are like ilogb except that
they return long int instead of int.  Corresponding FP_LLOGB* macros
are defined, whose values are required to have the obvious
correspondence to those of the FP_ILOGB* macros.

This patch implements these functions and macros for glibc.  llogb
uses the type-generic infrastructure, with an implementation similar
to the wrapper for ilogb but with additional conversion from FP_ILOGB*
to FP_LLOGB*; this approach avoids needing to modify or duplicate any
of the architecture-specific ilogb implementations.  Tests are also
based on those for ilogb.

Ideally the llogb functions would alias the ilogb ones when long is
32-bit, but such aliasing requires the associated header declarations
of the different-type alias to be hidden, typically by defining macros
before including the header (see e.g. how
sysdeps/ieee754/dbl-64/wordsize-64/s_llround.c defines lround to
__hidden_lround before including <math.h>).  The infrastructure for
type-generic function implementations does not support defining such
macros at present (since C code can't define a macro whose name is
determined by other macros).  So this patch leaves them as separate
functions (similar to e.g. scalbln and scalbn being separate in such a
case as well), but with the remapping of FP_ILOGB* to FP_LLOGB*
conditioned out in the case where it would be the identity map.

Tested for x86_64, x86, mips64 and powerpc.

	* math/bits/mathcalls.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (llogb):
	New declaration.
	* math/tgmath.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (llogb): New
	macro.
	* math/math.h [__GLIBC_USE (IEC_60559_BFP_EXT)] (__FP_LONG_MAX):
	New macro.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FP_LLOGB0): Likewise.
	[__GLIBC_USE (IEC_60559_BFP_EXT)] (FP_LLOGBNAN): Likewise.
	* math/Versions (llogb): New libm symbol at version GLIBC_2.25.
	(llogbf): Likewise.
	(llogbl): Likewise.
	* math/Makefile (gen-libm-calls): Add w_llogbF.
	(tests): Add test-fp-llogb-constants.
	* math/w_llogb_template.c: New file.  Based on
	math/w_ilogb_template.c.
	* math/libm-test.inc (llogb_test_data): New array.
	(llogb_test): New function.
	(main): Call llogb_test.
	* math/test-fp-llogb-constants.c: New file.  Based on
	math/test-fp-ilogb-constants.c.
	* math/test-tgmath-ret.c (llogb): New CHECK_RET_CONST call.
	(do_test): Call check_return_llogb.
	* math/test-tgmath.c (NCALLS): Increase to 126.
	(F(compile_test)): Call llogb.
	(F(llogb)): New function.
	* manual/math.texi (Exponents and Logarithms): Document llogb,
	llogbf, llogbl, FP_LLOGB0 and FP_LLOGBNAN.
	* manual/libm-err-tab.pl (@all_functions): Add llogb.
	* sysdeps/ieee754/ldbl-opt/nldbl-llogb.c: New file.
	* sysdeps/ieee754/ldbl-opt/w_llogbl.c: Likewise.
	* sysdeps/ieee754/ldbl-opt/Makefile (libnldbl-calls): Add llogb.
	(CFLAGS-nldbl-llogb.c): New variable.
	* sysdeps/nacl/libm.abilist: Update.
	* sysdeps/unix/sysv/linux/aarch64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/alpha/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/arm/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/hppa/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/i386/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/ia64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/m68k/coldfire/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/m68k/m680x0/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/microblaze/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips32/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/mips/mips64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/nios2/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/s390/s390-32/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/s390/s390-64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sh/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc32/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/sparc/sparc64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx32/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/tile/tilegx/tilegx64/libm.abilist:
	Likewise.
	* sysdeps/unix/sysv/linux/tile/tilepro/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/64/libm.abilist: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/x32/libm.abilist: Likewise.

10 files changed, 182 insertions, 5 deletions

diff --git a/math/Makefile b/math/Makefile
index ac3a90a..848b093 100644
--- a/math/Makefile
+++ b/math/Makefile
@@ -52,7 +52,7 @@ gen-libm-calls = cargF conjF cimagF crealF cabsF s_cacosF		  \
 		 k_casinhF s_csinhF k_casinhF s_csinhF s_catanhF s_catanF \
 		 s_ctanF s_ctanhF s_cexpF s_clogF s_cprojF s_csqrtF	  \
 		 s_cpowF s_clog10F s_fdimF s_nextdownF s_fmaxF s_fminF	  \
-		 s_nanF s_iseqsigF s_canonicalizeF w_ilogbF
+		 s_nanF s_iseqsigF s_canonicalizeF w_ilogbF w_llogbF
 
 libm-calls =								  \
 	e_acosF e_acoshF e_asinF e_atan2F e_atanhF e_coshF e_expF e_fmodF \
@@ -159,7 +159,7 @@ tests = test-matherr test-fenv atest-exp atest-sincos atest-exp2 basic-test \
 	test-fesetexcept-traps test-fetestexceptflag test-femode \
 	test-femode-traps test-iszero-excess-precision \
 	test-iseqsig-excess-precision test-flt-eval-method \
-	test-fp-ilogb-constants $(tests-static)
+	test-fp-ilogb-constants test-fp-llogb-constants $(tests-static)
 tests-static = test-fpucw-static test-fpucw-ieee-static \
 	       test-signgam-uchar-static test-signgam-uchar-init-static \
 	       test-signgam-uint-static test-signgam-uint-init-static \
diff --git a/math/Versions b/math/Versions
index 143e53f..6fe9bb7 100644
--- a/math/Versions
+++ b/math/Versions
@@ -223,5 +223,6 @@ libm {
     canonicalize; canonicalizef; canonicalizel;
     setpayload; setpayloadf; setpayloadl;
     setpayloadsig; setpayloadsigf; setpayloadsigl;
+    llogb; llogbf; llogbl;
   }
 }
diff --git a/math/bits/mathcalls.h b/math/bits/mathcalls.h
index 54ea4b8..c57b562 100644
--- a/math/bits/mathcalls.h
+++ b/math/bits/mathcalls.h
@@ -315,6 +315,11 @@ __MATHCALL (scalbn,, (_Mdouble_ __x, int __n));
 __MATHDECL (int,ilogb,, (_Mdouble_ __x));
 #endif
 
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Like ilogb, but returning long int.  */
+__MATHDECL (long int, llogb,, (_Mdouble_ __x));
+#endif
+
 #ifdef __USE_ISOC99
 /* Return X times (2 to the Nth power).  */
 __MATHCALL (scalbln,, (_Mdouble_ __x, long int __n));
diff --git a/math/libm-test.inc b/math/libm-test.inc
index 81d114b..85df9de 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -50,7 +50,7 @@
    ilogb, iscanonical, isfinite, isinf, isnan, isnormal, issignaling,
    issubnormal, iszero, iseqsig, isless, islessequal, isgreater,
    isgreaterequal, islessgreater, isunordered, j0, j1, jn,
-   ldexp, lgamma, log, log10, log1p, log2, logb,
+   ldexp, lgamma, llogb, log, log10, log1p, log2, logb,
    modf, nearbyint, nextafter, nexttoward,
    pow, pow10, remainder, remquo, rint, lrint, llrint,
    round, lround, llround,
@@ -9171,6 +9171,48 @@ gamma_test (void)
 }
 
 
+static const struct test_f_l_data llogb_test_data[] =
+  {
+    TEST_f_l (llogb, 1, 0, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_l (llogb, lit_e, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_l (llogb, 1024, 10, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_l (llogb, -2000, 10, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_l (llogb, 0.5, -1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED);
+    TEST_f_l (llogb, -0.5, -1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED);
+
+#if MANT_DIG >= 57
+    TEST_f_l (llogb, 0x1.ffffffffffffffp1L, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+    TEST_f_l (llogb, -0x1.ffffffffffffffp1L, 1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED),
+#endif
+
+    TEST_f_l (llogb, min_subnorm_value, MIN_EXP-MANT_DIG, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED);
+    TEST_f_l (llogb, -min_subnorm_value, MIN_EXP-MANT_DIG, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED);
+    TEST_f_l (llogb, min_value, MIN_EXP-1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED);
+    TEST_f_l (llogb, -min_value, MIN_EXP-1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED);
+    TEST_f_l (llogb, max_value, MAX_EXP-1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED);
+    TEST_f_l (llogb, -max_value, MAX_EXP-1, NO_INEXACT_EXCEPTION|ERRNO_UNCHANGED);
+
+    /* llogb (0.0) == FP_LLOGB0 plus invalid exception  */
+    TEST_f_l (llogb, 0.0, FP_LLOGB0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_f_l (llogb, -0.0, FP_LLOGB0, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    /* llogb (qNaN) == FP_LLOGBNAN plus invalid exception  */
+    TEST_f_l (llogb, qnan_value, FP_LLOGBNAN, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_f_l (llogb, -qnan_value, FP_LLOGBNAN, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_f_l (llogb, snan_value, FP_LLOGBNAN, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    TEST_f_l (llogb, -snan_value, FP_LLOGBNAN, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    /* llogb (inf) == LONG_MAX plus invalid exception  */
+    TEST_f_l (llogb, plus_infty, LONG_MAX, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+    /* llogb (-inf) == LONG_MAX plus invalid exception  */
+    TEST_f_l (llogb, minus_infty, LONG_MAX, NO_INEXACT_EXCEPTION|INVALID_EXCEPTION|ERRNO_EDOM),
+  };
+
+static void
+llogb_test (void)
+{
+  ALL_RM_TEST (llogb, 1, llogb_test_data, RUN_TEST_LOOP_f_l, END);
+}
+
+
 static const struct test_f_l_data lrint_test_data[] =
   {
     /* Bug 6798: errno setting may be missing.  */
@@ -13775,6 +13817,7 @@ main (int argc, char **argv)
   modf_test ();
   pow10_test ();
   ilogb_test ();
+  llogb_test ();
   scalb_test ();
   scalbn_test ();
   scalbln_test ();
diff --git a/math/math.h b/math/math.h
index 6e4bf9e..b8f4b41 100644
--- a/math/math.h
+++ b/math/math.h
@@ -97,11 +97,13 @@ typedef _Float128x double_t;
 # endif
 #endif
 
-/* Define macros for the return value of ilogb, based on
+/* Define macros for the return values of ilogb and llogb, based on
    __FP_LOGB0_IS_MIN and __FP_LOGBNAN_IS_MIN.
 
     FP_ILOGB0	Expands to a value returned by `ilogb (0.0)'.
     FP_ILOGBNAN	Expands to a value returned by `ilogb (NAN)'.
+    FP_LLOGB0	Expands to a value returned by `llogb (0.0)'.
+    FP_LLOGBNAN	Expands to a value returned by `llogb (NAN)'.
 
 */
 
@@ -118,6 +120,23 @@ typedef _Float128x double_t;
 #  define FP_ILOGBNAN	2147483647
 # endif
 #endif
+#if __GLIBC_USE (IEC_60559_BFP_EXT)
+# if __WORDSIZE == 32
+#  define __FP_LONG_MAX 0x7fffffffL
+# else
+#  define __FP_LONG_MAX 0x7fffffffffffffffL
+# endif
+# if __FP_LOGB0_IS_MIN
+#  define FP_LLOGB0	(-__FP_LONG_MAX - 1)
+# else
+#  define FP_LLOGB0	(-__FP_LONG_MAX)
+# endif
+# if __FP_LOGBNAN_IS_MIN
+#  define FP_LLOGBNAN	(-__FP_LONG_MAX - 1)
+# else
+#  define FP_LLOGBNAN	__FP_LONG_MAX
+# endif
+#endif
 
 /* Get information about long double.  */
 
diff --git a/math/test-fp-llogb-constants.c b/math/test-fp-llogb-constants.c
new file mode 100644
index 0000000..25bc004
--- /dev/null
+++ b/math/test-fp-llogb-constants.c
@@ -0,0 +1,48 @@
+/* Test requirements on FP_LLOGB* constants.
+   Copyright (C) 2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <limits.h>
+#include <math.h>
+
+#if FP_LLOGB0 >= 0
+# error "FP_LLOGB0 is positive"
+#endif
+
+#if FP_LLOGB0 != LONG_MIN && FP_LLOGB0 != -LONG_MAX
+# error "FP_LLOGB0 must be LONG_MIN or -LONG_MAX"
+#endif
+
+#if FP_LLOGBNAN >= 0 && FP_LLOGBNAN != LONG_MAX
+# error "FP_LLOGBNAN must be LONG_MIN or LONG_MAX"
+#endif
+
+#if FP_LLOGBNAN < 0 && FP_LLOGBNAN != LONG_MIN
+# error "FP_LLOGBNAN must be LONG_MIN or LONG_MAX"
+#endif
+
+#if (FP_ILOGB0 == INT_MIN) != (FP_LLOGB0 == LONG_MIN)
+# error "FP_ILOGB0 and FP_LLOGB0 inconsistent"
+#endif
+
+#if (FP_ILOGBNAN == INT_MIN) != (FP_LLOGBNAN == LONG_MIN)
+# error "FP_ILOGBNAN and FP_LLOGBNAN inconsistent"
+#endif
+
+/* This is a compilation test.  */
+#define TEST_FUNCTION 0
+#include "../test-skeleton.c"
diff --git a/math/test-tgmath-ret.c b/math/test-tgmath-ret.c
index 9f535b9..d7bcb5c 100644
--- a/math/test-tgmath-ret.c
+++ b/math/test-tgmath-ret.c
@@ -61,6 +61,7 @@ check_return_ ##func (void)						      \
 }
 
 CHECK_RET_CONST(ilogb, int)
+CHECK_RET_CONST(llogb, long)
 CHECK_RET_CONST(lrint, long)
 CHECK_RET_CONST(lround, long)
 CHECK_RET_CONST(llrint, long long)
@@ -70,6 +71,7 @@ static int
 do_test (void)
 {
   check_return_ilogb ();
+  check_return_llogb ();
   check_return_lrint ();
   check_return_lround ();
   check_return_llrint ();
diff --git a/math/test-tgmath.c b/math/test-tgmath.c
index a919c64..be2c2fc 100644
--- a/math/test-tgmath.c
+++ b/math/test-tgmath.c
@@ -50,7 +50,7 @@ int count_cdouble;
 int count_cfloat;
 int count_cldouble;
 
-#define NCALLS     125
+#define NCALLS     126
 #define NCALLS_INT 4
 #define NCCALLS    47
 
@@ -281,6 +281,7 @@ F(compile_test) (void)
   a = scalb (scalb (x, a), (TYPE) (6));
   k = scalbn (a, 7) + scalbln (c, 10l);
   i = ilogb (x);
+  j = llogb (x);
   a = fdim (fdim (x, a), fdim (c, b));
   b = fmax (fmax (a, x), fmax (c, b));
   a = fmin (fmin (x, a), fmin (c, b));
@@ -379,6 +380,7 @@ F(compile_test) (void)
       a = scalb (y, (const TYPE) (6));
       k = scalbn (y, 7) + scalbln (y, 10l);
       i = ilogb (y);
+      j = llogb (y);
       a = fdim (y, y);
       a = fmax (y, y);
       a = fmin (y, y);
@@ -846,6 +848,14 @@ int
   return x;
 }
 
+long int
+(F(llogb)) (TYPE x)
+{
+  ++count;
+  P ();
+  return x;
+}
+
 TYPE
 (F(fdim)) (TYPE x, TYPE y)
 {
diff --git a/math/tgmath.h b/math/tgmath.h
index 0d51ae6..95f5f19 100644
--- a/math/tgmath.h
+++ b/math/tgmath.h
@@ -438,6 +438,9 @@
      __TGMATH_TERNARY_REAL_ONLY (Val1, Val2, Val3, fma)
 
 #if __GLIBC_USE (IEC_60559_BFP_EXT)
+/* Like ilogb, but returning long int.  */
+#define llogb(Val) __TGMATH_UNARY_REAL_RET_ONLY (Val, long int, llogb)
+
 /* Total order operation.  */
 # define totalorder(Val1, Val2) __TGMATH_BINARY_REAL_ONLY (Val1, Val2,	\
 							   totalorder)
diff --git a/math/w_llogb_template.c b/math/w_llogb_template.c
new file mode 100644
index 0000000..9065bf9
--- /dev/null
+++ b/math/w_llogb_template.c
@@ -0,0 +1,46 @@
+/* Wrapper to implement llogb in terms of ilogb.
+   Copyright (C) 2012-2016 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#include <math.h>
+#include <errno.h>
+#include <limits.h>
+#include <math_private.h>
+
+long int
+M_DECL_FUNC (__llogb) (FLOAT x)
+{
+  int r = M_SUF (__ieee754_ilogb) (x);
+  long int lr = r;
+  if (__glibc_unlikely (r == FP_ILOGB0)
+      || __glibc_unlikely (r == FP_ILOGBNAN)
+      || __glibc_unlikely (r == INT_MAX))
+    {
+#if LONG_MAX != INT_MAX
+      if (r == FP_ILOGB0)
+	lr = FP_LLOGB0;
+      else if (r == FP_ILOGBNAN)
+	lr = FP_LLOGBNAN;
+      else
+	lr = LONG_MAX;
+#endif
+      __set_errno (EDOM);
+      __feraiseexcept (FE_INVALID);
+    }
+  return lr;
+}
+declare_mgen_alias (__llogb, llogb)