https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80986
Ramana Radhakrishnan <ramana at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |ramana at gcc dot gnu.org
--- Comment #4 from Ramana Radhakrishnan <ramana at gcc dot gnu.org> ---
(In reply to linzj from comment #2)
> I have found the cause of this bug.
> In 5.3, the function strip_typedefs only use
> result = cp_build_type_attribute_variant (result, TYPE_ATTRIBUTES (t));
> but in 6.3 remove_attributes prediction get invovled:
> if (TYPE_ATTRIBUTES (t))
> {
> if (remove_attributes)
> result = apply_identity_attributes (result, TYPE_ATTRIBUTES (t),
> remove_attributes);
> else
> result = cp_build_type_attribute_variant (result, TYPE_ATTRIBUTES (t));
> }
> and unfortunately the pcs attribute is declared as
> { "pcs", 1, 1, false, true, true, arm_handle_pcs_attribute,
> false },
> which affects_type_identity field is set to false, cause
> apply_identity_attributes
> drop this attribute.
Does affects_type_identity cause other user visible changes ? For e.g. based on
a cursory look it appears to affect mangling in C++. The comment in tree-core.h
simply says this affects the type's identity presumably implying that this
additionally adds value to the type's identity.
Almost all attributes I see in the front-ends or other backends has this set to
false and I'm certainly not happy switching this to true without understanding
the ramifications.
In the use case that is considered here, I can see that it makes a difference
however without understanding what else can change I'm not happy with the patch
going in.
