On Wed, Apr 19, 2023 at 11:02:53AM +0200, Jakub Jelinek wrote:
> Hi!
>
> The new -Wenum-int-mismatch warning triggers with -Wsystem-headers in
> <openacc.h>, for obvious reasons the builtin acc_on_device uses int
> type argument rather than enum which isn't defined yet when the builtin
> is created, while the OpenACC spec requires it to have acc_device_t
> enum argument. The header makes sure it has int underlying type by using
> negative and __INT_MAX__ enumerators.
>
> I've tried to make the builtin typegeneric or just varargs, but that
> changes behavior e.g. when one calls it with some C++ class which has
> cast operator to acc_device_t, so the following patch instead disables
> the warning for this builtin.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk
> and 13.2?
>
> 2023-04-19 Jakub Jelinek <ja...@redhat.com>
>
> PR c/107041
> * c-decl.cc (diagnose_mismatched_decls): Avoid -Wenum-int-mismatch
> warning on acc_on_device declaration.
>
> * gcc.dg/goacc/pr107041.c: New test.
>
> --- gcc/c/c-decl.cc.jj 2023-03-10 10:10:17.918387120 +0100
> +++ gcc/c/c-decl.cc 2023-04-18 10:29:33.340793562 +0200
> @@ -2219,7 +2219,14 @@ diagnose_mismatched_decls (tree newdecl,
> }
> /* Warn about enum/integer type mismatches. They are compatible types
> (C2X 6.7.2.2/5), but may pose portability problems. */
> - else if (enum_and_int_p && TREE_CODE (newdecl) != TYPE_DECL)
> + else if (enum_and_int_p
> + && TREE_CODE (newdecl) != TYPE_DECL
> + /* Don't warn about about acc_on_device builtin redeclaration,
"built-in"
> + the builtin is declared with int rather than enum because
"built-in"
> + the enum isn't intrinsic. */
> + && !(TREE_CODE (olddecl) == FUNCTION_DECL
> + && fndecl_built_in_p (olddecl, BUILT_IN_ACC_ON_DEVICE)
> + && !C_DECL_DECLARED_BUILTIN (olddecl)))
What do you think about adding an (UN)LIKELY here? This seems a rather
very special case. On the other hand we're not on a hot path here so it
hardly matters.
OK either way, thanks.
> warned = warning_at (DECL_SOURCE_LOCATION (newdecl),
> OPT_Wenum_int_mismatch,
> "conflicting types for %q+D due to enum/integer "
> --- gcc/testsuite/gcc.dg/goacc/pr107041.c.jj 2023-04-18 10:18:07.039754258
> +0200
> +++ gcc/testsuite/gcc.dg/goacc/pr107041.c 2023-04-18 10:17:21.252418797
> +0200
> @@ -0,0 +1,23 @@
> +/* PR c/107041 */
> +/* { dg-do compile } */
> +/* { dg-additional-options "-Wenum-int-mismatch" } */
> +
> +typedef enum acc_device_t {
> + acc_device_current = -1,
> + acc_device_none = 0,
> + acc_device_default = 1,
> + acc_device_host = 2,
> + acc_device_not_host = 4,
> + acc_device_nvidia = 5,
> + acc_device_radeon = 8,
> + _ACC_highest = __INT_MAX__
> +} acc_device_t;
> +
> +int acc_on_device (acc_device_t); /* { dg-bogus "conflicting
> types for 'acc_on_device' due to enum/integer mismatch; have
> 'int\\\(acc_device_t\\\)'" } */
> +int acc_on_device (acc_device_t);
> +
> +int
> +foo (void)
> +{
> + return acc_on_device (acc_device_host);
> +}
>
> Jakub
>
Marek
