[Bug tree-optimization/18046] Missed jump threading optimization

[dberlin at dberlin dot org]

------- Comment #11 from dberlin at gcc dot gnu dot org  2006-03-21 16:57 -------
Subject: Re:  Missed jump threading
        optimization

On Tue, 2006-03-21 at 15:57 +0000, law at redhat dot com wrote:
> 
> ------- Comment #9 from law at redhat dot com  2006-03-21 15:57 -------
> We've got zero chance of threading the jump in this case until the 
> partially redundant load from "i" is removed.
> 
> Daniel -- there's a pretty obvious redundant load from the global
> variable "i" in this testcase.  I haven't investigated why PRE
> is missing this obvious redundancy.

It doesn't deal with loads from global variables because we need to
place a value number on each "instance" that occurs in the program, but
can't easily because they are all shared.

I will get to it eventually.


> 
> Jeff
> 
> 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18046