On 23/08/2023 16:49, Richard Sandiford via Gcc-patches wrote:
> 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
I did think about that, but there were two reasons for not doing so:
- it presumes we would never want more than 8 bits for rtx_code (well, not
quite,
but it would make it more work to change this).
- it would probably lead to more zero-extension operations happening in the
compiler
I'll put my patch in as is.
R.
