[LLVMdev] Compiler opt is turned off ?

[Somenath Chakraborty]

I completely agree with you.

The source code I wrote here has the main function and is a complete code.
That's why I was expecting load/store analysis could have been incorporated
across the module. Thanks.

On Fri, Jan 4, 2013 at 10:43 PM, Daniel Berlin <dberlin at dberlin.org> wrote:

> I'm not sure what you mean by "use" check.
> If you compile this with LTO and multiple modules, and guarantee that
> you have the main function, yes, you could optimize this.
> In all other cases, it's not possible to eliminate any of the
> remaining loads or stores you see, because you have no guarantee about
> what else could read it.
>
> Heck, a conforming implementation of printf could read from any of
> these globals, so you don't even need other modules.
>
>
>
>
>
> On Fri, Jan 4, 2013 at 11:45 AM, Somenath Chakraborty
> <some.chak at gmail.com> wrote:
> > Thanks for your reply. So, we don't do any "use" check (for globals
> > variables) beyond a module scope. If so, it answers my question.
> >
> > On Fri, Jan 4, 2013 at 6:53 PM, Justin Holewinski
> > <justin.holewinski at gmail.com> wrote:
> >>
> >> Since a, b, and c are globals, how does the optimize *know* they are not
> >> used elsewhere (e.g. another module)?
> >
> >
> >
> > _______________________________________________
> > LLVM Developers mailing list
> > LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> > http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev
> >
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20130105/d3867cf7/attachment.html>