https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90204
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |rguenth at gcc dot gnu.org
--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
The difference is that for C++ we directly use DECL_RESULT in the GIMPLE IL
while for C we end up with a copy to it. The C++ FE does
;; Function v test(v, v) (null)
;; enabled by -tree-original
{
struct v res [value-expr: <retval>];
and at the end
<<cleanup_point return <retval>>>;
}
while the C FE uses plain res:
{
struct v res;
...
return res;
}
which in the end also results in try/finally processing for CLOBBERs. Not sure
where the C++ FE decides using <retval> for res is fine and whether the C
FE could do the same. Certainly eliding this extra copy is beneficial.
