[Bug target/78095] [7 Regression] valgrind build error on ppc64le

[wschmidt at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78095

--- Comment #7 from Bill Schmidt <wschmidt at gcc dot gnu.org> ---
(In reply to Markus Trippelsdorf from comment #6)
> At least it needs a big fat explanation in
> https://gcc.gnu.org/gcc-7/changes.html

I tend to think this is the right action.  It has never been a good idea to
clobber r2 with an inline asm, but it was previously undiagnosed.  The clobbers
in valgrind are wrong (and our valgrind guy is now aware this needs to be
fixed).

We can expect a round of similar bug reports for misguided asm, but these are
all user errors that will be worth exposing.

Anyone object if we add a note to gcc-7/change.html and close this as NOTABUG?