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Re: [tree-ssa] 'out_of_ssa_tag' question



On Jan 8, 2004, at 9:40 AM, Diego Novillo wrote:


On Wed, 2003-12-31 at 14:18, Devang Patel wrote:
On Dec 31, 2003, at 8:19 AM, Diego Novillo wrote:

OR am I taking wrong path by going in and out of SSA form for this
loop
transformation? Is it better to take care of SSA vars and phi nodes
while copying loop body ?

Well, it does seem a bit heavy handed. Maybe a better alternative
would
be to just mark the affected variables for renaming. So, you duplicate
the loop, insert all the variables referenced in the loop in the
vars_to_rename bitmap, and then call rewrite_into_ssa.

One problem with this approach is that candidate variable is referenced
in two loops and we want to rename only one. OR we want to inform ssa
renaming pass that they are different vars with same name.


Different vars with the same name? As in different VAR_DECLs with
*different* UIDs? If they are different VAR_DECLs, they'd better have
different UIDs. If you used add_referenced_tmp_var() then you should be
OK.


Marking one of them for renaming won't affect the other.  Now, if both
have the same UID and they're different variables, that will give you
headaches down the road.

I create second var for copy of loop using copy_node(), so I guess UIDs are not different. I did not use add_referenced_tmp_var(). I'll see how I can get different UID.

Thanks,
--
Devang


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