On 07/09/2010 11:34 AM, Mathieu Lacage wrote: > On Fri, Jul 9, 2010 at 11:33 AM, Andrew Haley <aph@xxxxxxxxxx> wrote: > >> g++ seems to be generating a specialization of run_cmp() in the >> __int128_t case, with the parameters a and b fixed at a=1 and b=2, in >> an attempt to do some constant propagation. This ought to help, but >> unfortunately the back-end generates worse code for the specialized >> case. > > Interesting: this is what the clone thing is about then. I found this > issue only because I am actually doing some benchmarking and am trying > to evaluate the average cost of a 128bit comparison (compared to other > things). Do you know of a way to convince gcc to not generate this > specialization so that I really measure the generic comparison > function ? I guess that I could pull the constant values from the > command line to ensure that gcc does not generate this specialization > but is there a better way ? Sure, just don't use constants for 1 and 2. Putting them as variables in file scope ought to do it. int one = 1; etc. Andrew. P.S. Please cc: me on copies, don't send a separate mail.
