[RFC] Remove double-int.

[Richard Biener]

On Mon, Sep 7, 2026 at 6:23 PM Kael Andrew Franco via Gcc
<gcc@gcc.gnu.org> wrote:
>
> double-int currently operates in 128 bit integers according to double-int.h.
> wide-int.h has fixed_wide_int, which does not use heap.
> This helps PR126622, simplifying build_int_cst-like functions,
> including the removal
> of double_int_to_tree.
> Beside double-int.{cc,h}, according to grep, double_int is used in:
>
> config/avr/avr.cc
> cp/parser.cc
> fixed-value.cc
> fixed-value.h
> go/go-gcc.cc
> emit-rtl.cc
> rtl.h
> dwarf2out.cc
> dwarf2out.h

ISTR this was one of the problematic uses (to replace),
size is very important here.  fixed_wide_int still stores 'len'.

In general I'd support dropping double_int uses in favor
of wide_int, but we have to look out for the loss of
efficiency (in size/speed?)

> wide-int.cc
> tree-pretty-print.cc
> tree-pretty-print.h
> fold-const.cc
> tree.cc
> tree.h
> gengtype.cc