[Bug target/66554] [4.9 Regression] ICE (in expand_fix, at optabs.c:5365) on aarch64-linux-gnu

["rguenth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66554

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to kugan from comment #6)
> -fno-tree-forwprop works.
> 
> forwprop propagates:
> vect__11.22_96 = (vector(4) float) vect_c.21_94;
> vect__13.24_98 = (vector(4) signed int) vect__11.22_96;
> 
> into:
> vect__13.24_98 = (vector(4) signed int) vect_c.21_94;
> 
> this seems to be the reason why we have expand_fix with V4SI in to mode and
> from mode. trunk code seems significantly different due to
> match-and-simplify.
> 
> 
> Should we disallow this propagation? Any thoughts?

So this is a sign-conversion only?  Because I can't see how we reach
expand_fix with V4SI -> V4SI...  unless the operation code remains a
FIX_TRUNC_EXPR which would be a bug.

Checking with a cross.