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Re: PATCH PING: stop ivopts from pessimizing code (PR42505)


Hi,

> Ping?
>
> http://gcc.gnu.org/ml/gcc-patches/2010-06/msg01920.html

what are the effects on the compile time? The tree-ssa-loop-ivopts.c part of the
patch is OK, assuming that they are negligible.

>> 2010-06-18  Sandra Loosemore  <sandra@codesourcery.com>
>>
>>     PR middle-end/42505
>>
>>     gcc/
>>     * tree-ssa-loop-ivopts.c (determine_set_costs): Delete obsolete
>>     comments about cost model.
>>     (try_add_cand_for):  Add second strategy for choosing initial set
>>     based on original IVs, controlled by ORIGINALP argument.
>>     (get_initial_solution): Add ORIGINALP argument.
>>     (find_optimal_iv_set_1): New function, split from find_optimal_iv_set.
>>     (find_optimal_iv_set): Try two different strategies for choosing
>>     the IV set, and return the one with lower cost.

As for this change:

>>     * cfgloopanal.c (init_set_costs): Use call_used_regs rather than
>>     fixed_regs to count number of registers available for loop variables.

Should not we make call_used_regs unavailable only if there is a function call in the
loop?

Zdenek


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