[Bug rtl-optimization/65067] regression on accessing volatile bit field

[bernd.edlinger at hotmail dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65067

--- Comment #8 from Bernd Edlinger <bernd.edlinger at hotmail dot de> ---
Created attachment 34955
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34955&action=edit
Proposed Fix

Well, I noticed that the first version of this patch caused
a small but measurable decrease of code quality on x86_64,
so I moved the patch to the if (strict_volatile_bitfield_p block,
and used some code transformations to simplify the resulting code
a bit.

I will post this new version for review, after a full boot-strap
and successful regression-test on my ARM target.