[gcc r13-8397] calls: Further fixes for TYPE_NO_NAMED_ARGS_STDARG_P handling [PR114136]

[Jakub Jelinek]

https://gcc.gnu.org/g:96e6576a1ba0080e70fef4a6f9cc3129fcf6f008

commit r13-8397-g96e6576a1ba0080e70fef4a6f9cc3129fcf6f008
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri Mar 1 15:42:52 2024 +0100

    calls: Further fixes for TYPE_NO_NAMED_ARGS_STDARG_P handling [PR114136]
    
    On Tue, Feb 27, 2024 at 04:41:32PM +0000, Richard Earnshaw wrote:
    > On Arm the PR107453 change is causing all anonymous arguments to be passed on the
    > stack, which is incorrect per the ABI.  On a target that uses
    > 'pretend_outgoing_vararg_named', why is it correct to set n_named_args to
    > zero?  Is it enough to guard both the statements you've added with
    > !targetm.calls.pretend_outgoing_args_named?
    
    The TYPE_NO_NAMED_ARGS_STDARG_P functions (C23 fns like void foo (...) {})
    have NULL type_arg_types, so the list_length (type_arg_types) isn't done for
    it, but it should be handled as if it was non-NULL but list length was 0.
    
    So, for the
      if (type_arg_types != 0)
        n_named_args
          = (list_length (type_arg_types)
             /* Count the struct value address, if it is passed as a parm.  */
             + structure_value_addr_parm);
      else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype))
        n_named_args = 0;
      else
        /* If we know nothing, treat all args as named.  */
        n_named_args = num_actuals;
    case, I think guarding it by any target hooks is wrong, although
    I guess it should have been
        n_named_args = structure_value_addr_parm;
    instead of
        n_named_args = 0;
    
    For the second
      if (type_arg_types != 0
          && targetm.calls.strict_argument_naming (args_so_far))
        ;
      else if (type_arg_types != 0
               && ! targetm.calls.pretend_outgoing_varargs_named (args_so_far))
        /* Don't include the last named arg.  */
        --n_named_args;
      else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype))
        n_named_args = 0;
      else
        /* Treat all args as named.  */
        n_named_args = num_actuals;
    I think we should treat those as if type_arg_types was non-NULL
    with 0 elements in the list, except the --n_named_args would for
    !structure_value_addr_parm lead to n_named_args = -1, I think we want
    0 for that case.
    
    2024-03-01  Jakub Jelinek  <jakub@redhat.com>
    
            PR middle-end/114136
            * calls.cc (expand_call): For TYPE_NO_NAMED_ARGS_STDARG_P set
            n_named_args initially before INIT_CUMULATIVE_ARGS to
            structure_value_addr_parm rather than 0, after it don't modify
            it if strict_argument_naming and clear only if
            !pretend_outgoing_varargs_named.
    
    (cherry picked from commit b5377928a2a5cd2a79eda59e2eba7d0511bf7566)

Diff:
---
 gcc/calls.cc | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/gcc/calls.cc b/gcc/calls.cc
index 4d7f6c3d291..53b0f58b709 100644
--- a/gcc/calls.cc
+++ b/gcc/calls.cc
@@ -2920,7 +2920,7 @@ expand_call (tree exp, rtx target, int ignore)
 	 /* Count the struct value address, if it is passed as a parm.  */
 	 + structure_value_addr_parm);
   else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype))
-    n_named_args = 0;
+    n_named_args = structure_value_addr_parm;
   else
     /* If we know nothing, treat all args as named.  */
     n_named_args = num_actuals;
@@ -2952,14 +2952,15 @@ expand_call (tree exp, rtx target, int ignore)
      we do not have any reliable way to pass unnamed args in
      registers, so we must force them into memory.  */
 
-  if (type_arg_types != 0
+  if ((type_arg_types != 0 || TYPE_NO_NAMED_ARGS_STDARG_P (funtype))
       && targetm.calls.strict_argument_naming (args_so_far))
     ;
   else if (type_arg_types != 0
 	   && ! targetm.calls.pretend_outgoing_varargs_named (args_so_far))
     /* Don't include the last named arg.  */
     --n_named_args;
-  else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype))
+  else if (TYPE_NO_NAMED_ARGS_STDARG_P (funtype)
+	   && ! targetm.calls.pretend_outgoing_varargs_named (args_so_far))
     n_named_args = 0;
   else
     /* Treat all args as named.  */