[Bug tree-optimization/32540] [4.3 Regression] Exponential time behavior in PRE

[rguenther at suse dot de]

------- Comment #9 from rguenther at suse dot de  2007-10-20 20:52 -------
Subject: Re:  [4.3 Regression] Exponential time
 behavior in PRE

On Sat, 20 Oct 2007, dberlin at dberlin dot org wrote:

> ------- Comment #8 from dberlin at gcc dot gnu dot org  2007-10-20 20:49 -------
> Subject: Re:  [4.3 Regression] Exponential time behavior in PRE
> 
> We may just want to disable PPRE of constants entirely :)

If you don't initialize the variable to zero we or in all the bits then
the value will be not constant, but still 'var | constant' with 2**24
different constants...

Richard.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32540