[Bug target/103353] Indefinite recursion when compiling -mmma requiring testcase w/ -maltivec

[segher at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103353

--- Comment #4 from Segher Boessenkool <segher at gcc dot gnu.org> ---
You miss all extra errors the expand_call can generate.  This is the general
reason why we try to continue instead of stopping after the first error.  The
reason is that later errors may be more obvious to the user.  This of course
does no longer work so well because our errors now take 30 lines instead of 1.

It probably is best if the generic opaque-mode emit_move code does not try
to move it via some other mode_class.  Peter?

Failing that, we can work around it by having move patterns for those modes
always, but hard erroring on them (FAIL is no good).