[Bug middle-end/59990] [4.7/4.8/4.9 regression] incorrect memcpy optimization

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59990

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Eric Botcazou from comment #7)
> > If it is ok that thiscase aborts and the #c0 should not, then the bug would
> > be in fold-const.c and we should use integral types instead of floating
> > point types to fold the copy.  If this testcase shouldn't abort too, then it
> > is a target issue, where it should avoid the i387 loads if the result isn't
> > used in some arithmetic instruction.
> 
> I disagree, using FP types to implement memcpy in the middle-end is a no-no,
> i387 isn't the only architecture which can fiddle with FP values.

I agree and I have a fix.  Fortunately it's very easy and cleans up the code
even ;)