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Re: [graphite] Backend fixes
- From: "Sebastian Pop" <sebpop at gmail dot com>
- To: "Tobias Grosser" <grosser at fim dot uni-passau dot de>
- Cc: "GCC Patches" <gcc-patches at gcc dot gnu dot org>
- Date: Mon, 25 Aug 2008 11:26:36 -0500
- Subject: Re: [graphite] Backend fixes
- References: <1219654702.1370.28.camel@localhost>
> Disable cloog optimizations
> ===========================
>
> * graphite.c (set_cloog_options): Disable optimizations.
>
> Cloog optimizes the output in control flow.
>
> Example:
>
> for (i = 0; i < 100; i ++)
> if (i < 30 && i > 60)
> A
> becomes:
>
> for (i = 0; i < 30; i++)
> A
> for (i = 61; i < 100; i++)
> A
>
> This breaks the current code generation, as some bbs may appear twice
> or more often in the clast output.
>
For fixing this one, we're replacing the bb_move with a bb_copy such
that we can handle also multiple copies of A. This triggers also the
need of another cleanup for induction variables: we need exactly one
IV per loop, otherwise we end up with variable definitions that
disappears, as not renamed or moved along from the old loop.
Sebastian