Doesn't CRAN R default to using -O2 flags when compiling C++ source files? (I think the default is -O3 for C source files).
Are you using CRAN R, or a locally built R? You might need to set that explicitly yourself when configuring R? On Tue, Aug 25, 2015 at 2:54 PM, Avraham Adler <avraham.ad...@gmail.com> wrote: > The -march is local, of course. The question is should Rcpp always > enforce at least -O2 or the like? From your answer I guess not. > > The reason why not to simply have an optimization flag in the local > makevars is that, at least in my experience, some code is faster with > O2 and some with O3, and by having one in makevars, I am overriding > the cases where the package author (who knows better) is passing a > different flag. Of course one can just add that flag and install Rcpp > by itself. > > Thanks again, > > Avi > > On Tue, Aug 25, 2015 at 5:50 PM, Dirk Eddelbuettel <e...@debian.org> wrote: >> >> On 25 August 2015 at 17:39, Avraham Adler wrote: >> | I've been testing a GCC 4.9.2-based toolchain for Windows for the last >> | week or so, and today fell afoul of the error uncovered here >> | <https://stat.ethz.ch/pipermail/r-devel/2015-March/070814.html>. I've >> | been passing different optimization flags, and Rcpp compiled properly >> | under every one EXCEPT when a -march (ivybridge) flag was passed >> | without an optimization flag. In that case, I received the >> | "collect2.exe: error: ld returned 5 exit status" error as discussed on >> | R-devel. Passing a -mtune flag without an -O flag did not cause an >> | error. >> | >> | Downloading the Rcpp source code and manually adding -O2 to Rcpp's >> | Makevars.win, re-tar/gzipping it and installing the local version >> | allowed Rcpp to compile properly. >> | >> | I don't know if it is better to tell people to change their local >> | Makevars under HOME/.R to pass -O2 or -O3 (that would probably be a >> | call by you, Dirk, as you would know best if O3 would help or hinder), >> | or if it is better to have Rcpp enforce it, but it should be noted >> | somewhere once a 4.9.2-based Windows is eventually released. >> >> CRAN disallows non-portable flags such as -march. >> >> So yes, ~/.R/Makevars it is. >> >> Dirk >> >> -- >> http://dirk.eddelbuettel.com | @eddelbuettel | e...@debian.org > _______________________________________________ > Rcpp-devel mailing list > Rcpp-devel@lists.r-forge.r-project.org > https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel _______________________________________________ Rcpp-devel mailing list Rcpp-devel@lists.r-forge.r-project.org https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
