Re: [PATCH] Remove conditional STATIC_ASSERT.

[Richard Biener <richard.guenther@gmail.com>]

On Thu, May 5, 2022 at 2:20 PM Martin Liška <mliska@suse.cz> wrote:
>
> As we require a c++11 compliant compiler, the #if __cplusplus >= 201103L
> conditional build is always true.
>
> Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
>
> Ready to be installed?

Can we then use static_assert (...) instead and remove the
macro?  Do we have C compiled code left (I think we might,
otherwise we'd not have __cplusplus guards in system.h),
in which case the #if should change to #ifdef __cplusplus?

Thanks,
Richard.

> Thanks,
> Martin
>
> gcc/ChangeLog:
>
>         * basic-block.h (STATIC_ASSERT): Use normal STATIC_ASSERT.
>         * system.h (STATIC_ASSERT): Define always as static_assert.
> ---
>  gcc/basic-block.h | 5 +----
>  gcc/system.h      | 9 +--------
>  2 files changed, 2 insertions(+), 12 deletions(-)
>
> diff --git a/gcc/basic-block.h b/gcc/basic-block.h
> index e3fff1f6975..21a9b24dbf9 100644
> --- a/gcc/basic-block.h
> +++ b/gcc/basic-block.h
> @@ -158,10 +158,7 @@ struct GTY((chain_next ("%h.next_bb"), chain_prev ("%h.prev_bb"))) basic_block_d
>  /* This ensures that struct gimple_bb_info is smaller than
>     struct rtl_bb_info, so that inlining the former into basic_block_def
>     is the better choice.  */
> -typedef int __assert_gimple_bb_smaller_rtl_bb
> -              [(int) sizeof (struct rtl_bb_info)
> -               - (int) sizeof (struct gimple_bb_info)];
> -
> +STATIC_ASSERT (sizeof (rtl_bb_info) >= sizeof (gimple_bb_info));
>
>  #define BB_FREQ_MAX 10000
>
> diff --git a/gcc/system.h b/gcc/system.h
> index 1688b763ef5..48145951337 100644
> --- a/gcc/system.h
> +++ b/gcc/system.h
> @@ -801,14 +801,7 @@ extern void fancy_abort (const char *, int, const char *)
>
>  #define STATIC_CONSTANT_P(X) (__builtin_constant_p (X) && (X))
>
> -/* static_assert (COND, MESSAGE) is available in C++11 onwards.  */
> -#if __cplusplus >= 201103L
> -#define STATIC_ASSERT(X) \
> -  static_assert ((X), #X)
> -#else
> -#define STATIC_ASSERT(X) \
> -  typedef int assertion1[(X) ? 1 : -1] ATTRIBUTE_UNUSED
> -#endif
> +#define STATIC_ASSERT(X) static_assert ((X), #X)
>
>  /* Provide a fake boolean type.  We make no attempt to use the
>     C99 _Bool, as it may not be available in the bootstrap compiler,
> --
> 2.36.0
>