On Sat, Aug 3, 2013 at 1:06 AM, Jan Hubicka <hubi...@ucw.cz> wrote: >> 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 <davi...@google.com> >> >> * params.def: New parameters. >> * config/i386/i386.c (ix86_option_override_internal): >> Override default libcall size limit with parameters. > > Hi, > problem with this is that we introduce generic --param that is used only > by x86 backend. I am not really guru on the command line options, but I think > this is first time we try to do such thing. I wonder if > 1) We want to introduce target specific params.def
We do have target specific tuning code for parameters though -- backend overrides the default value -- I think this is essentially target specific params. > 2) We want to use usual -msomething= options > 3) We want to go this way? I don't have strong opinion either way. To avoid controversy, let me work on a -mxxx= version of the patch -- and hopefully it will be more powerful. thanks, David > > Honza
