[Bug tree-optimization/71050] [7 regression] test case gcc.target/powerpc/lhs-1.c fails starting with r236066

[wschmidt at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71050

--- Comment #6 from Bill Schmidt <wschmidt at gcc dot gnu.org> ---
Yes, I see your point -- even if you query the RTX cost of the subreg, we're
just going to tell you it's one insn since the true expense doesn't show up
until reload.  Seems like some invention will be required.