Re: [PATCH] rtl: Forward declare rtx_code

[Richard Sandiford via Gcc-patches]

Richard Earnshaw via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
> Now that we require C++ 11, we can safely forward declare rtx_code
> so that we can use it in target hooks.
>
> gcc/ChangeLog
>       * coretypes.h (rtx_code): Add forward declaration.
>       * rtl.h (rtx_code): Make compatible with forward declaration.
> ---
>  gcc/coretypes.h | 4 ++++
>  gcc/rtl.h       | 2 +-
>  2 files changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/coretypes.h b/gcc/coretypes.h
> index ca8837cef67..51e55559ce0 100644
> --- a/gcc/coretypes.h
> +++ b/gcc/coretypes.h
> @@ -100,6 +100,10 @@ struct gimple;
>  typedef gimple *gimple_seq;
>  struct gimple_stmt_iterator;
>  
> +/* Forward declare rtx_code, so that we can use it in target hooks without
> +   needing to pull in rtl.h.  */
> +enum rtx_code : unsigned;
> +
>  /* Forward decls for leaf gimple subclasses (for individual gimple codes).
>     Keep this in the same order as the corresponding codes in gimple.def.  */
>  
> diff --git a/gcc/rtl.h b/gcc/rtl.h
> index e1c51156f90..0e9491b89b4 100644
> --- a/gcc/rtl.h
> +++ b/gcc/rtl.h
> @@ -45,7 +45,7 @@ class predefined_function_abi;
>  /* Register Transfer Language EXPRESSIONS CODES */
>  
>  #define RTX_CODE     enum rtx_code
> -enum rtx_code  {
> +enum rtx_code : unsigned {
>  
>  #define DEF_RTL_EXPR(ENUM, NAME, FORMAT, CLASS)   ENUM ,
>  #include "rtl.def"           /* rtl expressions are documented here */

Given:

  #define RTX_CODE_BITSIZE 8

there might be some value in making it uint8_t rather than unsigned.
Preapproved if you agree.

But the patch as posted is a strict improvement over the status quo,
so it's also OK as-is.

Thanks,
Richard