[Bug target/126484] error: too few argu ments to function ‘unsigned int __builtin_m ips_get_fcsr(void)`

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126484

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org,
                   |                            |syq at gcc dot gnu.org

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
The mips backend creates the builtin function type incorrectly.
mips-ftypes.def:      VOID for void_type_node
#define MIPS_ATYPE_VOID void_type_node
and later constructed with:
    types[(int) type]                                                   \
      = build_function_type_list (MIPS_FTYPE_ATYPES##NUM ARGS,          \
                                  NULL_TREE);                           \
The point of () functions is that for
DEF_MIPS_FTYPE (1, (SI, VOID))
DEF_MIPS_FTYPE (1, (USI, VOID))
those actually should be instead using omitting that argument, so that the
argument list is void_list_node.
I'd think e.g.
--- gcc/config/mips/mips-ftypes.def.jj  2026-03-27 10:17:13.895334639 +0100
+++ gcc/config/mips/mips-ftypes.def     2026-07-29 22:46:31.097286998 +0200
@@ -75,7 +75,7 @@ DEF_MIPS_FTYPE (1, (SI, V4QI))
 DEF_MIPS_FTYPE (2, (SI, V4QI, V4QI))
 DEF_MIPS_FTYPE (2, (SI, V4SI, UQI))
 DEF_MIPS_FTYPE (2, (SI, V8HI, UQI))
-DEF_MIPS_FTYPE (1, (SI, VOID))
+DEF_MIPS_FTYPE (0, (SI, VOID))

 DEF_MIPS_FTYPE (2, (UDI, UDI, UDI))
 DEF_MIPS_FTYPE (2, (UDI, UV2SI, UV2SI))
@@ -84,7 +84,7 @@ DEF_MIPS_FTYPE (2, (UDI, V2DI, UQI))
 DEF_MIPS_FTYPE (2, (USI, V16QI, UQI))
 DEF_MIPS_FTYPE (2, (USI, V4SI, UQI))
 DEF_MIPS_FTYPE (2, (USI, V8HI, UQI))
-DEF_MIPS_FTYPE (1, (USI, VOID))
+DEF_MIPS_FTYPE (0, (USI, VOID))

 DEF_MIPS_FTYPE (2, (UV16QI, UV16QI, UQI))
 DEF_MIPS_FTYPE (2, (UV16QI, UV16QI, UV16QI))
--- gcc/config/mips/mips.cc.jj  2026-06-30 09:20:44.087805722 +0200
+++ gcc/config/mips/mips.cc     2026-07-29 22:48:04.576110764 +0200
@@ -211,6 +211,7 @@ enum mips_ucbranch_type
 };

 /* Macros to create an enumeration identifier for a function prototype.  */
+#define MIPS_FTYPE_NAME0(A, B) MIPS_##A##_FTYPE_##B
 #define MIPS_FTYPE_NAME1(A, B) MIPS_##A##_FTYPE_##B
 #define MIPS_FTYPE_NAME2(A, B, C) MIPS_##A##_FTYPE_##B##_##C
 #define MIPS_FTYPE_NAME3(A, B, C, D) MIPS_##A##_FTYPE_##B##_##C##_##D
@@ -17137,6 +17138,9 @@ mips_build_cvpointer_type (void)

 /* MIPS_FTYPE_ATYPESN takes N MIPS_FTYPES-like type codes and lists
    their associated MIPS_ATYPEs.  */
+#define MIPS_FTYPE_ATYPES0(A, B) \
+  MIPS_ATYPE_##A
+
 #define MIPS_FTYPE_ATYPES1(A, B) \
   MIPS_ATYPE_##A, MIPS_ATYPE_##B

perhaps could fix it, but mips isn't a target I've ever tested nor care about
much, so will defer to maintainers.