stdlib: Implement C2Y uabs, ulabs, ullabs and uimaxabs

C2Y adds unsigned versions of the abs functions (see C2Y draft N3467 and
proposal N3349).

Tested for x86_64.

Signed-off-by: Lenard Mollenkopf <glibc@lenardmollenkopf.de>

47 files changed, 475 insertions, 2 deletions

diff --git a/NEWS b/NEWS
index 703f08a166..c8dc31925e 100644
--- a/NEWS
+++ b/NEWS
@@ -18,6 +18,9 @@ Major new features:
 
 * On Linux, the pthread_gettid_np function has been added.
 
+* The ISO C2Y family of unsigned abs functions, i.e.
+  uabs, ulabs, ullabs and uimaxabs, are now supported.
+
 Deprecated and removed features, and other changes affecting compatibility:
 
   [Add deprecations, removals and changes affecting compatibility here]
diff --git a/manual/arith.texi b/manual/arith.texi
index 034d9d2ba5..d500dcf2a9 100644
--- a/manual/arith.texi
+++ b/manual/arith.texi
@@ -1233,25 +1233,33 @@ whose imaginary part is @var{y}, the absolute value is @w{@code{sqrt
 
 @pindex math.h
 @pindex stdlib.h
-Prototypes for @code{abs}, @code{labs} and @code{llabs} are in @file{stdlib.h};
-@code{imaxabs} is declared in @file{inttypes.h};
+Prototypes for @code{abs}, @code{labs}, @code{llabs},
+@code{uabs}, @code{ulabs} and @code{ullabs} are in @file{stdlib.h};
+@code{imaxabs} and @code{uimaxabs} are declared in @file{inttypes.h};
 the @code{fabs} functions are declared in @file{math.h};
 the @code{cabs} functions are declared in @file{complex.h}.
 
 @deftypefun int abs (int @var{number})
 @deftypefunx {long int} labs (long int @var{number})
 @deftypefunx {long long int} llabs (long long int @var{number})
+@deftypefunx {unsigned int} uabs (int @var{number})
+@deftypefunx {unsigned long int} ulabs (long int @var{number})
+@deftypefunx {unsigned long long int} ullabs (long long int @var{number})
 @deftypefunx intmax_t imaxabs (intmax_t @var{number})
+@deftypefunx uintmax_t uimaxabs (intmax_t @var{number})
 @standards{ISO, stdlib.h}
 @standardsx{imaxabs, ISO, inttypes.h}
+@standardsx{uimaxabs, ISO, inttypes.h}
 @safety{@prelim{}@mtsafe{}@assafe{}@acsafe{}}
 These functions return the absolute value of @var{number}.
 
 Most computers use a two's complement integer representation, in which
 the absolute value of @code{INT_MIN} (the smallest possible @code{int})
 cannot be represented; thus, @w{@code{abs (INT_MIN)}} is not defined.
+Using @code{uabs} avoids this.
 
 @code{llabs} and @code{imaxdiv} are new to @w{ISO C99}.
+@code{uabs}, @code{ulabs}, @code{ullabs} and @code{uimaxabs} are new to @w{ISO C2Y}.
 
 See @ref{Integers} for a description of the @code{intmax_t} type.
 
diff --git a/stdlib/Makefile b/stdlib/Makefile
index 513445bcbc..1c80e497f0 100644
--- a/stdlib/Makefile
+++ b/stdlib/Makefile
@@ -211,6 +211,9 @@ routines := \
   strtoull_l \
   swapcontext \
   system \
+  uabs \
+  ulabs \
+  ullabs \
   wcstombs \
   wctomb  \
   xpg_basename \
@@ -363,6 +366,10 @@ tests := \
   tst-swapcontext2 \
   tst-thread-quick_exit \
   tst-tininess \
+  tst-uabs \
+  tst-uimaxabs \
+  tst-ulabs \
+  tst-ullabs \
   tst-unsetenv1 \
   tst-width \
   tst-width-stdint \
@@ -412,6 +419,11 @@ CFLAGS-tst-abs.c += -fno-builtin
 CFLAGS-tst-labs.c += -fno-builtin
 CFLAGS-tst-llabs.c += -fno-builtin
 
+CFLAGS-tst-uabs.c += -fno-builtin
+CFLAGS-tst-uimaxabs.c += -fno-builtin
+CFLAGS-tst-ulabs.c += -fno-builtin
+CFLAGS-tst-ullabs.c += -fno-builtin
+
 CFLAGS-tst-stdbit-Wconversion.c += -Wconversion -Werror
 CFLAGS-tst-stdc_trailing_zeros.c += -fno-builtin
 CFLAGS-tst-stdc_trailing_ones.c += -fno-builtin
diff --git a/stdlib/Versions b/stdlib/Versions
index ea2265bbd4..6d024000f8 100644
--- a/stdlib/Versions
+++ b/stdlib/Versions
@@ -223,6 +223,12 @@ libc {
     stdc_bit_ceil_ul;
     stdc_bit_ceil_ull;
   }
+  GLIBC_2.42 {
+    uabs;
+    uimaxabs;
+    ulabs;
+    ullabs;
+  }
   GLIBC_PRIVATE {
     # functions which have an additional interface since they are
     # are cancelable.
diff --git a/stdlib/inttypes.h b/stdlib/inttypes.h
index 95324f0784..9726abf5b1 100644
--- a/stdlib/inttypes.h
+++ b/stdlib/inttypes.h
@@ -350,6 +350,11 @@ typedef struct
 /* Compute absolute value of N.  */
 extern intmax_t imaxabs (intmax_t __n) __THROW __attribute__ ((__const__));
 
+
+#if __GLIBC_USE (ISOC2Y)
+extern uintmax_t uimaxabs (intmax_t __n) __THROW __attribute__ ((__const__));
+#endif
+
 /* Return the `imaxdiv_t' representation of the value of NUMER over DENOM. */
 extern imaxdiv_t imaxdiv (intmax_t __numer, intmax_t __denom)
       __THROW __attribute__ ((__const__));
diff --git a/stdlib/stdlib.h b/stdlib/stdlib.h
index 975f5aeb0b..cd4503c761 100644
--- a/stdlib/stdlib.h
+++ b/stdlib/stdlib.h
@@ -985,6 +985,12 @@ __extension__ extern long long int llabs (long long int __x)
      __THROW __attribute__ ((__const__)) __wur;
 #endif
 
+#if __GLIBC_USE (ISOC2Y)
+extern unsigned int uabs (int __x) __THROW __attribute__ ((__const__)) __wur;
+extern unsigned long int ulabs (long int __x) __THROW __attribute__ ((__const__)) __wur;
+__extension__ extern unsigned long long int ullabs (long long int __x)
+     __THROW __attribute__ ((__const__)) __wur;
+#endif
 
 /* Return the `div_t', `ldiv_t' or `lldiv_t' representation
    of the value of NUMER over DENOM. */
diff --git a/stdlib/tst-uabs.c b/stdlib/tst-uabs.c
new file mode 100644
index 0000000000..13c9f58dc0
--- /dev/null
+++ b/stdlib/tst-uabs.c
@@ -0,0 +1,45 @@
+/* Basic tests for uabs.
+   Copyright (C) 2025 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <limits.h>
+#include <stdlib.h>
+
+#include <support/check.h>
+
+#define LARGE_PRIME 49999
+
+static int do_test (void)
+{
+  int i;
+
+  TEST_COMPARE (uabs (INT_MAX), INT_MAX);
+  TEST_COMPARE (uabs (INT_MIN), (unsigned int)INT_MAX + 1);
+  TEST_COMPARE (uabs (-1), 1);
+  TEST_COMPARE (uabs (0), 0);
+  TEST_COMPARE (uabs (1), 1);
+
+  for (i = INT_MIN + 1; i < 0; i += LARGE_PRIME)
+    TEST_COMPARE (uabs (i), -i);
+
+  for (i = 0; i < INT_MAX - LARGE_PRIME; i += LARGE_PRIME)
+    TEST_COMPARE (uabs (i), i);
+
+  return EXIT_SUCCESS;
+}
+
+#include <support/test-driver.c>
diff --git a/stdlib/tst-uimaxabs.c b/stdlib/tst-uimaxabs.c
new file mode 100644
index 0000000000..4500ec1797
--- /dev/null
+++ b/stdlib/tst-uimaxabs.c
@@ -0,0 +1,51 @@
+/* Basic tests for uimaxabs.
+   Copyright (C) 2025 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <inttypes.h>
+#include <limits.h>
+#include <stdlib.h>
+
+#include <support/check.h>
+
+#define LARGE_PRIME 49999
+
+static int do_test (void)
+{
+  intmax_t i;
+
+  TEST_COMPARE (uimaxabs (INTMAX_MIN), (uintmax_t)INTMAX_MAX + 1);
+  TEST_COMPARE (uimaxabs (-1), 1);
+  TEST_COMPARE (uimaxabs (0), 0);
+  TEST_COMPARE (uimaxabs (1), 1);
+
+  for (i = INTMAX_MIN + 1; i < INTMAX_MIN + INT_MAX; i += LARGE_PRIME)
+    TEST_COMPARE (uimaxabs (i), -i);
+
+  for (i = INTMAX_MAX - INT_MAX; i < INTMAX_MAX - LARGE_PRIME; i += LARGE_PRIME)
+    TEST_COMPARE (uimaxabs (i), i);
+
+  for (i = INT_MIN + 1; i < 0; i += LARGE_PRIME)
+    TEST_COMPARE (uimaxabs (i), -i);
+
+  for (i = 0; i < INT_MAX; i += LARGE_PRIME)
+    TEST_COMPARE (uimaxabs (i), i);
+
+  return EXIT_SUCCESS;
+}
+
+#include <support/test-driver.c>
diff --git a/stdlib/tst-ulabs.c b/stdlib/tst-ulabs.c
new file mode 100644
index 0000000000..3b5323e051
--- /dev/null
+++ b/stdlib/tst-ulabs.c
@@ -0,0 +1,52 @@
+/* Basic tests for ulabs.
+   Copyright (C) 2025 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <limits.h>
+#include <stdlib.h>
+
+#include <support/check.h>
+
+#define LARGE_PRIME 49999
+
+static int do_test (void)
+{
+  long int i;
+
+  TEST_COMPARE (ulabs (LONG_MAX), LONG_MAX);
+  TEST_COMPARE (ulabs (LONG_MIN), (unsigned long int)LONG_MAX + 1);
+  TEST_COMPARE (ulabs (-1), 1);
+  TEST_COMPARE (ulabs (0), 0);
+  TEST_COMPARE (ulabs (1), 1);
+
+  for (i = LONG_MIN + 1; i < LONG_MIN + INT_MAX; i += LARGE_PRIME)
+    TEST_COMPARE (ulabs (i), -i);
+
+  for (i = LONG_MAX - INT_MAX; i < LONG_MAX - LARGE_PRIME;
+       i += LARGE_PRIME)
+    TEST_COMPARE (ulabs (i), i);
+
+  for (i = INT_MIN + 1; i < 0; i += LARGE_PRIME)
+    TEST_COMPARE (ulabs (i), -i);
+
+  for (i = 0; i <= INT_MAX - LARGE_PRIME; i += LARGE_PRIME)
+    TEST_COMPARE (ulabs (i), i);
+
+  return EXIT_SUCCESS;
+}
+
+#include <support/test-driver.c>
diff --git a/stdlib/tst-ullabs.c b/stdlib/tst-ullabs.c
new file mode 100644
index 0000000000..ac34ec776e
--- /dev/null
+++ b/stdlib/tst-ullabs.c
@@ -0,0 +1,55 @@
+/* Basic tests for ullabs.
+   Copyright (C) 2025 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 GN