[RFC][4.4] Conversion of tree.h STRIP_* macros into static inline functions

[Simon Baldwin]

Tom Tromey wrote:
>>>>>> "Simon" == Simon Baldwin <simonb@google.com> writes:
>>>>>>             
>
> Simon> The attached file, gzipped because it exceeds 100Kb, is a patch
> Simon> that converts tree.h STRIP_* macros into static inline
> Simon> functions.
>
> I think it would be good to mark these functions with
> __attribute__((warn_unused_result)).  Otherwise, I think, it would be
> easy to accidentally call one erroneously -- for instance by bringing
> in an old-style use when doing a merge.
>   

Thanks for the feedback and suggestion.  I'd vaguely considered this as 
part of the patch, but didn't do it once I'd convinced myself I'd found 
all of the (current) call sites.  As you note, though, this neglects 
merge problems.

Added, then.

> Also, in this particular case, in my opinion, it would be better to
> lowercase the function names.  This would have the nice effect of
> breaking bad code that resulted from a merge.
>   

When the general issue of lowercasing converted and inlined macros came 
up a couple of months ago, the overall consensus was to leave them 
uppercased, because of disinclination to edit all call sites.

However, all call sites have to be edited for this particular patch 
anyway, so there's an argument for lowercasing them.

For the moment, however, I'm inclined to leave them alone.  The first 
reason is that this may be one of a series of semi-mechanical changes, 
so establishing a pattern seems useful.  The second, more prosaic, is 
that if STRIP_*() are documented anywhere, it'll be their uppercased 
versions that are documented; I'd prefer not to break any such 
documentation.  Or more accurately, I'd prefer not to have to find and 
update the documentation!

We can always decide to lowercase these and any other converted and 
inlined macros at some later date.

> Finally, I noticed a new declaration of
> tree_ssa_useless_type_conversion in tree.h.  Given that users of
> STRIP_USELESS_TYPE_CONVERSION had to include tree-flow.h to see
> the declaration, I think it would be preferable to move
> STRIP_USELESS_TYPE_CONVERSION there.
>   

Moving STRIP_USELESS_TYPE_CONVERSION from tree.h and into to 
tree-flow-inline.h, included by tree-flow.h, seems like the best course 
here, so that's what I've done.  This eliminates the duplicated 
tree_ssa_useless_type_conversion declaration.

Retesting now... guess I'll be mailing a revised version of the patch on 
test completion.

Again, thanks for the comments.