[LLVMdev] Compiler opt is turned off ?
some.chak at gmail.com
Sat Jan 5 03:17:19 PST 2013
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)?
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