[google] Limit unrolling and peeling under LIPO estimates of large code size/icache pressure

[Teresa Johnson <tejohnson at google dot com>]

This patch is for google-main only.
Tested with bootstrap and regression tests.
Under LIPO, estimate the code size footprint from the partial call
graph, and if it is large limit unrolling and peeling to avoid
increasing icache pressure.
Teresa

2011-11-21   Teresa Johnson  <tejohnson@google.com>

        * loop-unroll.c (loop_has_FP_comp): New function.
        (limit_code_size): New function.
        (unroll_and_peel_loops): Check if unrolling and/or peeling
        should be disabled due to large code size estimates.
        * common.opt (fripa-peel-size-limit): New option.
        (fripa-unroll-size-limit): New option.
        * tree-optimize.c (compute_codesize_estimate): New function.
        (execute_cleanup_cfg_post_optimizing): Invoke
        compute_codesize_estimate at the end of tree optimization.
        * params.def (codesize-hotness-threshold): New parameter.
        (unrollpeel-codesize-threshold): New parameter.
        * doc/invoke.texi: Document the new options and parameters.


-- 
Teresa Johnson?|?Software Engineer?|?tejohnson@google.com?|?408-460-2413

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