tree-sra.c and BIT_FIELD_REF?

[Jay K]

Our front end is wierd.
The input is unusually low level, and so are the trees it produces.
I do have a hankering to fix that (or maybe just to output more portable C...)
But for now:
It doesn't use component_refs, and doesn't
define types much, but uses either
either (type*)(base + offset) or bitfield_ref(base, offset, size).


As such, it runs into occasional problems.
I have had to turn off various optimizations with e.g.:
 flag_tree_sra = false
in langhook_post_options.



Looking at this briefly, I think I see one of the problems.
tree-sra.c looks for component_refs to bitfields, but
it doesn't look for bitfield_refs. It should?


also, in fold-const:
      /* A bit-field-ref that referenced the full argument can be stripped.  */


should probably check that the other type is integral
and that the signedness matches.


 - Jay