RE: [PATCH 1/1] gdb, fortran: Fix quad floating-point type for ifort compiler.

["Willgerodt, Felix" <felix.willgerodt@intel.com>]

> >>>>> "Felix" == Willgerodt, Felix via Gdb-patches <gdb-
> patches@sourceware.org> writes:
> 
> Felix> || strcmp (name, "_Float128") == 0
> Felix> || strcmp (name, "complex _Float128") == 0
> Felix> || strcmp (name, "complex(kind=16)") == 0
> Felix> +	|| strcmp (name, "COMPLEX(16)") == 0
> Felix> || strcmp (name, "complex*32") == 0
> Felix> || strcmp (name, "COMPLEX*32") == 0
> Felix> || strcmp (name, "quad complex") == 0
> Felix> || strcmp (name, "real(kind=16)") == 0
> Felix> || strcmp (name, "real*16") == 0
> Felix> -	|| strcmp (name, "REAL*16") == 0)
> Felix> +	|| strcmp (name, "REAL*16") == 0
> Felix> +	|| strcmp (name, "REAL(16)") == 0)
> Felix> return floatformats_ieee_quad;
> 
> >> Not your fault but this whole approach seems bad.
> 
> Felix> Agreed. But can we change anything really?
> 
> I suppose ideally what we would need is extra information in the DWARF.
> 
> Although... i386_floatformat_for_type is explicitly checking for
> len==128.  Is there some other float format matching this on i386?

As far as I know, the actual x87 FPU supports only an extended-double
format with 80 bits and the SSE/AVX units only support double-precision.
default_floatformat_for_type() has an explicit comment about it as well.

When examining memory for this Fortran test, I see 128-bit values in
binary128 format, so I assume that this is just a software/compiler feature. 
There is also decimal128 support in e.g. gcc.  I tried it only briefly,
we don't end up in i386_floatformat_for_type for those types, but
GDB prints them just fine.  I assume as they are marked as
DW_ATE_decimal_float instead of DW_ATE_float, but I didn't look into 
it in detail.

I am not aware of any other float types that exist with this length.

Felix
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