New parameters to control stringop expansion libcall strategy

[Xinliang David Li <davidxl at google dot com>]

On x86_64, when the expected size of memcpy/memset is known (e.g, with
FDO), libcall strategy is used with the size is > 8192. This value is
hard coded, which makes it hard to do performance tuning. This patch
adds two new parameters to do that. Potential usage includes
per-application libcall strategy min-size tuning based on summary data
with FDO (e.g, instruction workset size).

Bootstrap and tested on x86_64/linux. Ok for trunk?

thanks,

David


2013-08-02  Xinliang David Li  <davidxl@google.com>

        * params.def: New parameters.
        * config/i386/i386.c (ix86_option_override_internal):
        Override default libcall size limit with parameters.

Attachment: stringop_inl_param.txt
Description: Text document