[Bug middle-end/103393] [12 Regression] Generating 256bit register usage with -mprefer-avx128 -mprefer-vector-width=128

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103393

--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
In particular MOVE_RATIO only looks applicable if the target (or RTL
expansion?) would split the bigger GIMPLE move into pieces honoring MOVE_MAX. 
Though technically even MOVE_MAX only guarantees:

"The maximum number of bytes that a single instruction can move _QUICKLY_
between memory and registers or between two memory locations."

(emphasis mine)