------- Additional Comments From pinskia at physics dot uc dot edu 2005-09-19
16:44 -------
Subject: Re: SSA_NAMEs are not released after no longer being used.
On Sep 19, 2005, at 12:33 PM, amacleod at redhat dot com wrote:
> "And that will not work for the SSA_NAMEs used for aliasing and then
> the
> variable becomes a gimple register."
>
> If we set SSA_NAME_DEF_FOR_STMT during inserts, and clear it during
> bsi_remove,
> does that resolve the issues you are referring to?
We don't call bsi_remove for those statements so SSA_NAME_DEF_FOR_STMT
is always
set to that statement even though the SSA_NAME is unused.
The testcase (-O1 -fno-tree-fre) from my orginal email on the subject:
int f(void)
{
int i;
int *j = &i;
i = 1;
return *j;
}
SSA form right before .alias2:
# i_4 = V_MUST_DEF <i_3>;
i = tt_2;
D.1274_5 = tt_2;
return tt_2;
After:
i_1 = tt_2;
D.1274_5 = tt_2;
return tt_2;
Note that i_4 is not freed and its SSA_NAME_DEF_FOR_STMT is NULLd.
Thanks,
Andrew Pinski
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23940
