r192521 - Add missing flags -fexpensive-optimizations and -minline-all-stringops as noops.

[Joerg Sonnenberger]

On Tue, Oct 15, 2013 at 02:07:06PM -0700, Chandler Carruth wrote:
> On Tue, Oct 15, 2013 at 1:53 PM, Joerg Sonnenberger <joerg at britannica.bec.de
> > wrote:
> 
> > On Mon, Oct 14, 2013 at 04:58:55PM -0700, Chandler Carruth wrote:
> > > Whether it is correct or not, people were not using
> > -minline-all-stringops
> > > to avoid calling out to libc for them, they were using it as equivalent
> > to
> > > -O9 or whatever. =/ By ignoring this flag we correctly compile a
> > nontrivial
> > > amount of code out there.
> >
> > My gut instinct tells me that it might be the path of least resistence
> > to silently accept -fexpensive-optimisations, but that it doesn't make
> > sense to give -minline-all-stringops the same threatment. I am going to
> > run some field study now to verify the intuition. I can already say that
> > there are a number of wtf moments ahead...
> 
> 
> For the record, we ran plenty of field experiments ourselves. We have had
> no problems with this.
> 
> And in fact, I'm moderately confident we wont run into any *new* ones
> because as Nick pointed out ages ago in this thread, Clang used to ignore
> this flag, and every clang release has ignored this flag! We have never
> released a Clang compiler which rejected this flag.

I am well aware of what clang is doing and was doing. I know also quite
well how much fun it is to hunt down regressions both to silently
ignored options and new failures due to unknown ones. What I am testing
right now is whether the "nontrivial amount of code" exists or not.

Joerg