[Bug target/94254] [10 regression] r10-7312 causes compiler hangs

[rsandifo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94254

--- Comment #7 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> ---
Created attachment 48080
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=48080&action=edit
Proof-of-concept hack to back up the point in comment 4

This hack shows what I mean in comment 4.  It "fixes" the three
testcases but almost certainly isn't correct.  The point is that
before r10-7312 we did the mode change regardless of what
rs6000_can_change_mode_class said.

I don't know enough about powerpc to know what cases:

          if (from_size < 8 || to_size < 8)
            return false;

is handling.