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, 22 insertions, 0 deletions

diff --git a/math/Versions b/math/Versions
index 1a25b2ce9a..a4b5405ddc 100644
--- a/math/Versions
+++ b/math/Versions
@@ -599,6 +599,20 @@ libm {
     f32fmaf32x; f32fmaf64; f32xfmaf64;
     fsqrt; fsqrtl; dsqrtl;
     f32sqrtf32x; f32sqrtf64; f32xsqrtf64;
+    fmaximum; fmaximumf; fmaximuml; fmaximumf32; fmaximumf64; fmaximumf32x;
+    fmaximum_num; fmaximum_numf; fmaximum_numl;
+    fmaximum_numf32; fmaximum_numf64; fmaximum_numf32x;
+    fmaximum_mag; fmaximum_magf; fmaximum_magl;
+    fmaximum_magf32; fmaximum_magf64; fmaximum_magf32x;
+    fmaximum_mag_num; fmaximum_mag_numf; fmaximum_mag_numl;
+    fmaximum_mag_numf32; fmaximum_mag_numf64; fmaximum_mag_numf32x;
+    fminimum; fminimumf; fminimuml; fminimumf32; fminimumf64; fminimumf32x;
+    fminimum_num; fminimum_numf; fminimum_numl;
+    fminimum_numf32; fminimum_numf64; fminimum_numf32x;
+    fminimum_mag; fminimum_magf; fminimum_magl;
+    fminimum_magf32; fminimum_magf64; fminimum_magf32x;
+    fminimum_mag_num; fminimum_mag_numf; fminimum_mag_numl;
+    fminimum_mag_numf32; fminimum_mag_numf64; fminimum_mag_numf32x;
     # Functions involving _Float64x or _Float128, for some configurations.
     f32fmaf64x; f32fmaf128;
     f32xfmaf64x; f32xfmaf128; f64fmaf64x; f64fmaf128;
@@ -606,5 +620,13 @@ libm {
     f32sqrtf64x; f32sqrtf128;
     f32xsqrtf64x; f32xsqrtf128; f64sqrtf64x; f64sqrtf128;
     f64xsqrtf128;
+    fmaximumf64x; fmaximumf128;
+    fmaximum_numf64x; fmaximum_numf128;
+    fmaximum_magf64x; fmaximum_magf128;
+    fmaximum_mag_numf64x; fmaximum_mag_numf128;
+    fminimumf64x; fminimumf128;
+    fminimum_numf64x; fminimum_numf128;
+    fminimum_magf64x; fminimum_magf128;
+    fminimum_mag_numf64x; fminimum_mag_numf128;
   }
 }