[PATCH] calls: Fix up TYPE_NO_NAMED_ARGS_STDARG_P handling [PR107453]

[Jakub Jelinek <jakub@redhat.com>]

Hi!

On powerpc64le-linux, the following patch fixes
-FAIL: gcc.dg/c2x-stdarg-4.c execution test
-FAIL: gcc.dg/torture/c2x-stdarg-split-1a.c   -O0  execution test
-FAIL: gcc.dg/torture/c2x-stdarg-split-1a.c   -O1  execution test
-FAIL: gcc.dg/torture/c2x-stdarg-split-1a.c   -O2  execution test
-FAIL: gcc.dg/torture/c2x-stdarg-split-1a.c   -O2 -flto -fno-use-linker-plugin -flto-partition=none  execution test
-FAIL: gcc.dg/torture/c2x-stdarg-split-1a.c   -O2 -flto -fuse-linker-plugin -fno-fat-lto-objects  execution test
-FAIL: gcc.dg/torture/c2x-stdarg-split-1a.c   -O3 -g  execution test
-FAIL: gcc.dg/torture/c2x-stdarg-split-1a.c   -Os  execution test
The problem is mismatch between the caller and callee side.
On the callee side, we do:
  /* NAMED_ARG is a misnomer.  We really mean 'non-variadic'. */
  if (!cfun->stdarg)
    data->arg.named = 1;  /* No variadic parms.  */
  else if (DECL_CHAIN (parm))
    data->arg.named = 1;  /* Not the last non-variadic parm. */
  else if (targetm.calls.strict_argument_naming (all->args_so_far))
    data->arg.named = 1;  /* Only variadic ones are unnamed.  */
  else
    data->arg.named = 0;  /* Treat as variadic.  */
which is later passed to the target hooks to determine if a particular
argument is named or not.  Now, cfun->stdarg is determined from the stdarg_p
call, which for the new C2X TYPE_NO_NAMED_ARGS_STDARG_P function types
(rettype fn (...)) returns true.  Such functions have no named arguments,
so data->arg.named will be 0 in function.cc.  But on the caller side,
as TYPE_NO_NAMED_ARGS_STDARG_P function types have TYPE_ARG_TYPES NULL,
we instead treat those calls as unprototyped even when they are prototyped
- /* If we know nothing, treat all args as named.  */ n_named_args = num_actuals;
in 2 spots.  We need to treat the TYPE_NO_NAMED_ARGS_STDARG_P cases as
prototyped with no named arguments.

Bootstrapped/regtested on x86_64-linux, i686-linux, powerpc64le-linux (where
it fixes the above failures), aarch64-linux and s390x-linux, ok for trunk?

2023-01-09  Jakub Jelinek  <jakub@redhat.com>

	PR target/107453
	* calls.cc (expand_call): For calls with
	TYPE_NO_NAMED_ARGS_STDARG_P (funtype) use zero for n_named_args.
	Formatting fix.

--- gcc/calls.cc.jj	2023-01-02 09:32:28.834192105 +0100
+++ gcc/calls.cc	2023-01-06 14:52:14.740594896 +0100
@@ -2908,8 +2908,8 @@ expand_call (tree exp, rtx target, int i
     }
 
   /* Count the arguments and set NUM_ACTUALS.  */
-  num_actuals =
-    call_expr_nargs (exp) + num_complex_actuals + structure_value_addr_parm;
+  num_actuals
+    = call_expr_nargs (exp) + num_complex_actuals + structure_value_addr_parm;
 
   /* Compute number of named args.
      First, do a raw count of the args for INIT_CUMULATIVE_ARGS.  */
@@ -2919,6 +2919,8 @@ expand_call (tree exp, rtx target, int i
       = (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;
@@ -2957,6 +2959,8 @@ expand_call (tree exp, rtx target, int i
 	   && ! 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;

	Jakub