Re: [PATCH] Update array address space in c_build_qualified_type

[Joseph Myers <joseph@codesourcery.com>]

On Wed, 21 Jun 2023, Richard Biener via Gcc-patches wrote:

> >   This patch sets the address space of the array type to that of the
> >   element type.
> >
> >   Regression tests for avr look ok. Ok for trunk?
> 
> The patch looks OK to me but please let a C frontend maintainer
> double-check (I've CCed Joseph for this).

The question would be whether there are any TYPE_QUALS uses in the C front 
end that behave incorrectly given TYPE_ADDR_SPACE (acting as qualifiers) 
being set on an array type - conceptually, before C2x, array types are 
unqualified, only the element types are qualified.

The fact that this changed in C2x gives a shortcut to doing that analysis 
- you don't need to check all TYPE_QUALS uses in the front end, only a 
limited number of places that might handle qualifiers on arrays that 
already have conditionals to do things differently in C2x mode.  But some 
sort of analysis of those places, to see how they'd react to an array type 
itself having TYPE_ADDR_SPACE set, would be helpful.  If you're lucky, all 
those places only care about TYPE_QUALS on the element type and not on the 
array type itself.

-- 
Joseph S. Myers
joseph@codesourcery.com