[releng_6 tinderbox] failure on sparc64/sparc64

[Dag-Erling Smørgrav]

Warner Losh <imp at bsdimp.com> writes:
> Can we not have special flags for tinderbox builds?  It make
> pre-commit testing a big pita.  How about just -O on both head and
> in RELENG_6?

As I have repeatedly pointed out in the past, -O2 catches more bugs
because it enables optimizations which require more extensive coverage
analysis.

> The kernel make files have special magic to disable the parts of -O2
> that are known to be bad because tinderbox uses -O2, despite efforts
> in the past to stop the practice.

The kernel has special magic to disable strict aliasing checks because
certain people regularly commit kernel code which violates C aliasing
rules and refuse to fix it.  The userland code does not need these
hacks because I spent a lot of time and effort fixing aliasing bugs in
e.g. libalias.

Aliasing violations are not trivial matters; they prevent the compiler
from optimizing code which (for instance) accesses structure members
through pointers to the structure.  There is a lot of this in the
kernel.

DES
-- 
Dag-Erling Smørgrav - des at des.no