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Re: [gimplefe] Parsing PHI functions
- From: Richard Biener <richard dot guenther at gmail dot com>
- To: Prasad Ghangal <prasad dot ghangal at gmail dot com>
- Cc: gcc Mailing List <gcc at gcc dot gnu dot org>
- Date: Wed, 29 Jun 2016 09:12:17 +0200
- Subject: Re: [gimplefe] Parsing PHI functions
- Authentication-results: sourceware.org; auth=none
- References: <CAE+uiWYGhK8+Y55zmVwZx_zTrdruTdrmShdp6=Z=5-Yc7Gipmw at mail dot gmail dot com>
On Tue, Jun 28, 2016 at 4:16 PM, Prasad Ghangal
> For handling PHI, it expects cfg to be built before. So I was
> wondering how are we going to handle this? Do we need to build cfg
> while parsing only?
For handling PHIs we need to have a CFG in the sense that the GIMPLE PHI
data structures are built in a way to have the PHI argument index correspond
to CFG predecessor edge index. As we'd like to parse phis with args
to predecessor block labels, like
i_1 = 1;
i_2 = 2;
i_3 = __PHI (a: i_1, b: i_2);
I think that a possibility is to leave those PHIs as internal function
with label / arg
pairs and have CFG construction lower them to real PHIs.
Of course the parser could as well build a CFG on its own but I think
we should use
the easy way out for now.
Thus you'd have to modify CFG construction a bit to lower the internal