I will apply this patch.
While we still have a problem about
```
float max(float a, float b) { return a>=b?a:b; }
```
If it is compiled with `-ffinite-math-only -fsigned-zeros -O2
-mips32r6 -mabi=32`,
`max.s` can be used.
The max.fmt/min.fmt of MIPSr6 can process +0/-0 correctly.
This patch adds the smin/smax RTL mode for the
min/max.fmt instructions.
Also, since the min/max.fmt instrucions applies to the
IEEE 754-2008 "minNum" and "maxNum" operations, this
patch also provides the new "fmin3" and
"fmax3" modes.
gcc/ChangeLog:
* config/mips/i6400.md (i6400_fpu_min
