Add fmaximum, fminimum functions

C2X adds new <math.h> functions for floating-point maximum and
minimum, corresponding to the new operations that were added in IEEE
754-2019 because of concerns about the old operations not being
associative in the presence of signaling NaNs.  fmaximum and fminimum
handle NaNs like most <math.h> functions (any NaN argument means the
result is a quiet NaN).  fmaximum_num and fminimum_num handle both
quiet and signaling NaNs the way fmax and fmin handle quiet NaNs (if
one argument is a number and the other is a NaN, return the number),
but still raise "invalid" for a signaling NaN argument, making them
exceptions to the normal rule that a function with a floating-point
result raising "invalid" also returns a quiet NaN.  fmaximum_mag,
fminimum_mag, fmaximum_mag_num and fminimum_mag_num are corresponding
functions returning the argument with greatest or least absolute
value.  All these functions also treat +0 as greater than -0.  There
are also corresponding <tgmath.h> type-generic macros.

Add these functions to glibc.  The implementations use type-generic
templates based on those for fmax, fmin, fmaxmag and fminmag, and test
inputs are based on those for those functions with appropriate
adjustments to the expected results.  The RISC-V maintainers might
wish to add optimized versions of fmaximum_num and fminimum_num (for
float and double), since RISC-V (F extension version 2.2 and later)
provides instructions corresponding to those functions - though it
might be at least as useful to add architecture-independent built-in
functions to GCC and teach the RISC-V back end to expand those
functions inline, which is what you generally want for functions that
can be implemented with a single instruction.

Tested for x86_64 and x86, and with build-many-glibcs.py.

1 files changed, 81 insertions, 1 deletions

diff --git a/math/test-tgmath.c b/math/test-tgmath.c
index 6ec7760c62..f9b5fc640f 100644
--- a/math/test-tgmath.c
+++ b/math/test-tgmath.c
@@ -48,7 +48,7 @@ volatile int count_cdouble;
 volatile int count_cfloat;
 volatile int count_cldouble;
 
-#define NCALLS     132
+#define NCALLS     156
 #define NCALLS_INT 4
 #define NCCALLS    47
 
@@ -290,6 +290,14 @@ F(compile_test) (void)
   a = fmin (fmin (x, a), fmin (c, b));
   b = fmaxmag (fmaxmag (a, x), fmaxmag (c, b));
   a = fminmag (fminmag (x, a), fminmag (c, b));
+  b = fmaximum (fmaximum (a, x), fmaximum (c, b));
+  a = fminimum (fminimum (x, a), fminimum (c, b));
+  b = fmaximum_num (fmaximum_num (a, x), fmaximum_num (c, b));
+  a = fminimum_num (fminimum_num (x, a), fminimum_num (c, b));
+  b = fmaximum_mag (fmaximum_mag (a, x), fmaximum_mag (c, b));
+  a = fminimum_mag (fminimum_mag (x, a), fminimum_mag (c, b));
+  b = fmaximum_mag_num (fmaximum_mag_num (a, x), fmaximum_mag_num (c, b));
+  a = fminimum_mag_num (fminimum_mag_num (x, a), fminimum_mag_num (c, b));
   b = fma (sin (a), sin (x), sin (c));
 
 #ifdef TEST_INT
@@ -393,6 +401,14 @@ F(compile_test) (void)
       a = fmin (y, y);
       a = fmaxmag (y, y);
       a = fminmag (y, y);
+      a = fmaximum (y, y);
+      a = fminimum (y, y);
+      a = fmaximum_num (y, y);
+      a = fminimum_num (y, y);
+      a = fmaximum_mag (y, y);
+      a = fminimum_mag (y, y);
+      a = fmaximum_mag_num (y, y);
+      a = fminimum_mag_num (y, y);
       a = fma (y, y, y);
 
 #ifdef TEST_INT
@@ -944,6 +960,70 @@ TYPE
 }
 
 TYPE
+(F(fminimum)) (TYPE x, TYPE y)
+{
+  ++count;
+  P ();
+  return x + y;
+}
+
+TYPE
+(F(fmaximum)) (TYPE x, TYPE y)
+{
+  ++count;
+  P ();
+  return x + y;
+}
+
+TYPE
+(F(fminimum_num)) (TYPE x, TYPE y)
+{
+  ++count;
+  P ();
+  return x + y;
+}
+
+TYPE
+(F(fmaximum_num)) (TYPE x, TYPE y)
+{
+  ++count;
+  P ();
+  return x + y;
+}
+
+TYPE
+(F(fminimum_mag)) (TYPE x, TYPE y)
+{
+  ++count;
+  P ();
+  return x + y;
+}
+
+TYPE
+(F(fmaximum_mag)) (TYPE x, TYPE y)
+{
+  ++count;
+  P ();
+  return x + y;
+}
+
+TYPE
+(F(fminimum_mag_num)) (TYPE x, TYPE y)
+{
+  ++count;
+  P ();
+  return x + y;
+}
+
+TYPE
+(F(fmaximum_mag_num)) (TYPE x, TYPE y)
+{
+  ++count;
+  P ();
+  return x + y;
+}
+
+TYPE
 (F(fma)) (TYPE x, TYPE y, TYPE z)
 {
   ++count;