Re: [MIPS][LS2][3/5] Miscellaneous instructions

[Maxim Kuvyrkov <maxim at codesourcery dot com>]

Maxim Kuvyrkov wrote:
> Richard Sandiford wrote:
>
> ...
>
> > > ;; This mode macro allows :ANYF_MIPS5_LS2 to be used wherever
> > > ;; a scalar or Loongson2 vector floating-point mode is allowed.
> > > (define_mode_macro ANYF_MIPS5_LS2
> > >   [(SF "TARGET_HARD_FLOAT")
> > >    (DF "TARGET_HARD_FLOAT && TARGET_DOUBLE_FLOAT")
> > >    (V2SF "TARGET_PAIRED_SINGLE_FLOAT_MIPS5_LS2")])
> > >
> > > Hence the instructions from MIPS5 ISA, which happen to be supported 
> > > by Loongson2, are declared with ANYF_MIPS5_LS2 mode_iterator.  I 
> > > don't like this, but can't figure out alternative way to name / 
> > > describe these instructions.
> >
> > I'd prefer to keep TARGET_PAIRED_SINGLE_FLOAT for the cases that
> > are common between Loongson and non-Loongson mode (i.e. the cases in
> > which .ps is available in some form).  Then add new ISA_HAS_FOO
> > macros for each class of instruction that Loongson doesn't have.
> > E.g.
> >
> >     ISA_HAS_PXX_PS
> >
> > for PUU.PS & co.
> >
> > Feel free to run a list of ISA_HAS_* macros by me before testing.
>
> How does the following patch look?  Now the patch disables certain .ps 
> instruction when compiling for Loongson and uses everything else (in 
> contrast, previous version enabled instruction that Loongson does 
> support and disabled everything else).
>
> I also noticed that the previous version of the patch didn't enable 
> [n]madd3/msub3 instructions and fixed that in this one.

During testing I discovered that the last version of the patch doesn't 
properly handles paired-single float builtins.

The last field in mips_builtin_description is target_flags.  For all 
builtins for paired-single float instructions target_flags is 
MASK_PAIRED_SINGLE_FLOAT.  As this mask specifies backend to support all 
paired-single float instruction Loongson gets too much intrinsics it 
can't back up.

I think, I misunderstood your original suggestion to make 
MASK_PAIRED_SINGLE_FLOAT to specify instructions that both Loongson and 
generic MIPS5 have.  If so, then we need a new mask to use with builtins 
that MIPS5 supports and Loongson doesn't.

--
Maxim