[Bug tree-optimization/18595] [4.0 Regression] IV-OPTS is O(N^3)

["dberlin at dberlin dot org" <gcc-bugzilla@gcc.gnu.org>]

------- Additional Comments From dberlin at gcc dot gnu dot org  2005-01-25 01:15 -------
Subject: Re:  [4.0 Regression] IV-OPTS is O(N^3)


> Which one? I cannot find anything relevant in changelog.
>


         * tree-data-ref.c (analyze_subscript_affine_affine): Implement a
         solution for the FIXME concerning the symbolic affine
         dependence testing; remove the FIXME.
         (can_use_analyze_subscript_affine_affine): New function.
         (analyze_siv_subscript): Use it.

and


2004-12-15  Daniel Berlin  <dberlin@dberlin.org>

         * Makefile.in (tree-chrec.o): Add cfgloop.h

         * tree-chrec.c: Add cfgloop.h, tree-flow.h.
         (evolution_function_is_invariant_p): New function.
         (evolution_function_is_affine_multivariate_p): Use
         evolution_function_is_invariant_p instead of
         evolution_function_is_constant_p.

         * tree-chrec.h: Add prototype for
         evolution_function_is_invariant_p.
         (evolution_function_is_affine_p): Use
         evolution_function_is_invariant_p.

         * tree-data-ref.c (analyze_overlapping_iterations): chrecs that
         are equal overlap on every iteration.

This stuff is just simple symbolic differencing, and checking of 
invariantness of symbols,
But it is indeed starting to se the symbolic scev info



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18595