MAX_FIXED_MODE_SIZE vs. __attribute__(mode) vs. ABIs

[Richard Henderson]

On Sun, Jan 02, 2005 at 06:42:54AM -0700, Roger Sayle wrote:
> Any advice would be appreciated.

MAX_FIXED_MODE_SIZE should be deprecated.  About the only thing that
it should be used for right now is mode assigment for aggregates.

As for 

	typedef int DItype __attribute__ ((mode (DI)));
	extern DItype foo();
	DItype bar()
	{
	  return foo() + 1;
	}

if the target doesn't want to support DImode for the user, then it
should reject the mode with targetm.scalar_mode_supported_p.

I see that c_common_nodes_and_builtins only checks that for TImode,
but there's no reason we shouldn't for all of the other modes as well.
Although, since we *do* check in handle_mode_attribute, I don't see
how the user should be getting past this.  Perhaps a bug somewhere?



r~