Re: [PATCH] Detect whether target can use -fprofile-update=atomic

[Jakub Jelinek <jakub at redhat dot com>]

On Tue, Sep 06, 2016 at 03:13:09PM +0200, Martin Liška wrote:
> @@ -535,6 +549,27 @@ tree_profiling (void)
>  {
>    struct cgraph_node *node;
>  
> +  /* Verify whether we can utilize atomic update operations.  */
> +  if (flag_profile_update == PROFILE_UPDATE_ATOMIC)
> +    {
> +      bool can_support = false;
> +      if (sizeof (gcov_type) == 4)
> +	can_support
> +	  = HAVE_sync_compare_and_swapsi || HAVE_atomic_compare_and_swapsi;
> +      else if (sizeof (gcov_type) == 8)
> +	can_support
> +	  = HAVE_sync_compare_and_swapdi || HAVE_atomic_compare_and_swapdi;
> +      else
> +	gcc_unreachable ();

sizeof (gcov_type) talks about the host gcov type, you want instead the
target gcov type.  So
TYPE_SIZE (gcov_type_node) == 32 vs. 64 (or TYPE_SIZE_UNIT (gcov_type_node)
== 4 vs. 8).
As SImode and DImode are in fact 4*BITS_PER_UNIT and 8*BITS_PER_UNIT,
TYPE_SIZE_UNIT comparisons for 4 and 8 are most natural.
And I wouldn't add gcc_unreachable, just warn for weirdo arches always.

	Jakub