On Thu, Feb 29, 2024 at 05:23:25PM +0000, Richard Earnshaw (lists) wrote: > On 29/02/2024 15:55, Jakub Jelinek wrote: > > On Thu, Feb 29, 2024 at 02:14:05PM +0000, Richard Earnshaw wrote: > >>> I tried the above on arm, aarch64 and x86_64 and that seems fine, > >>> including the new testcase you added. > >>> > >> > >> I should mention though, that INIT_CUMULATIVE_ARGS on arm ignores > >> n_named_args entirely, it doesn't need it (I don't think it even existed > >> when the AAPCS code was added). > > > > So far I've just checked that the new testcase passes not just on > > x86_64/i686-linux, but also on {powerpc64le,s390x,aarch64}-linux > > with vanilla trunk. > > Haven't posted this patch in patch form, plus while I'm not really sure > > whether setting n_named_args to 0 or not changing in the > > !pretend_outgoing_varargs_named is right, the setting to 0 feels more > > correct to me. If structure_value_addr_parm is 1, the function effectively > > has a single named argument and then ... args and if the target wants > > n_named_args to be number of named arguments except the last, then that > > should be 0 rather than 1. > > > > Thus, is the following patch ok for trunk then? > > The comment at the start of the section says > > /* Now possibly adjust the number of named args. > Normally, don't include the last named arg if anonymous args follow. > We do include the last named arg if > targetm.calls.strict_argument_naming() returns nonzero. > (If no anonymous args follow, the result of list_length is actually > one too large. This is harmless.) > > So in the case of strict_argument_naming perhaps it should return 1, but 0 > for other cases.
The TYPE_NO_NAMED_ARGS_STDARG_P (funtype) case is as if type_arg_types != 0 and list_length (type_arg_types) == 0, i.e. no user named arguments. As list_length (NULL) returns 0, perhaps it could be even handled just the by changing all the type_arg_types != 0 checks to type_arg_types != 0 || TYPE_NO_NAMED_ARGS_STDARG_P (funtype) There are just 2 cases I'm worried about, one is that I think rest of calls.cc nor the backends are prepared to see n_named_args -1 after the adjustments, I think it is better to use 0, and then the question is what the !strict_argument_naming && !pretend_outgoing_varargs_named case wants to do for the aggregate return. The patch as posted for void foo (...); void bar () { foo (1, 2, 3); } will set n_named_args initially to 0 (no named args) and with the adjustments for strict_argument_naming 0, otherwise for !pretend 0 as well, otherwise 3. For struct { char buf[4096]; } baz (...); void qux () { baz (1, 2, 3); } the patch sets n_named_args initially to 1 (the hidden return) and with the arguments for strict keep it at 1, for !pretend 0 and otherwise 3. So, which case do you think is handled incorrectly with that? Jakub