RISC-V: Fix C23 (...) functions returning large aggregates [PR114175]

We assume that TYPE_NO_NAMED_ARGS_STDARG_P don't have any named arguments and
there is nothing to advance, but that is not the case for (...) functions
returning by hidden reference which have one such artificial argument.
This causes gcc.dg/c23-stdarg-[68].c to fail

Fix the issue by checking if arg.type is NULL as r14-9503-g218d1749612
explains

Tested on linux rv64gcv.

gcc/ChangeLog:

	PR target/114175
	* config/riscv/riscv.cc (riscv_setup_incoming_varargs): Only skip
	riscv_funciton_arg_advance for TYPE_NO_NAMED_ARGS_STDARG_P functions
	if arg.type is NULL

(cherry picked from commit 60586710b0646efdbbd77a7f53b93fb5edb87a61)

diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index 01eebc83cc58410d8a66e7642923e34ef5da18e4..cefd3b7b2b23ff08499ab7243100719a4349a1a7 100644 (file)
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -3961,7 +3961,8 @@ riscv_setup_incoming_varargs (cumulative_args_t cum,
      argument.  Advance a local copy of CUM past the last "real" named
      argument, to find out how many registers are left over.  */
   local_cum = *get_cumulative_args (cum);
-  if (!TYPE_NO_NAMED_ARGS_STDARG_P (TREE_TYPE (current_function_decl)))
+  if (!TYPE_NO_NAMED_ARGS_STDARG_P (TREE_TYPE (current_function_decl))
+      || arg.type != NULL_TREE)
     riscv_function_arg_advance (pack_cumulative_args (&local_cum), arg);
 
   /* Found out how many registers we need to save.  */