Hi Loic, FWIW something with the build or feature detection seems to be off, as I just got an Illegal Instruction signal on the current master: http://tracker.ceph.com/issues/7826 sage On Sun, 23 Mar 2014, Loic Dachary wrote: > Hi Laurent, > > In the context of optimizing erasure code functions implemented by Kevin Greenan (cc'ed) and James Plank at https://bitbucket.org/jimplank/gf-complete/ we ran accross a question you may have the answer to: can gcc -msse2 (or -msse* for that matter ) have a negative impact on the portability of the compiled binary code ? > > In other words, if a code is compiled without -msse* and runs fine on all intel processors it targets, could it be that adding -msse* to the compilation of the same source code generate a binary that would fail on some processors ? This is assuming no sse specific functions were used in the source code. > > In gf-complete, all sse specific instructions are carefully protected to not be run on a CPU that does not support them. The runtime detection is done by checking CPU id bits ( see https://bitbucket.org/jimplank/gf-complete/pull-request/7/probe-intel-sse-features-at-runtime/diff#Lsrc/gf_intel.cT28 ) > > The corresponding thread is at: > > https://bitbucket.org/jimplank/gf-complete/pull-request/4/defer-the-decision-to-use-a-given-sse/diff#comment-1479296 > > Cheers > > -- > Loïc Dachary, Artisan Logiciel Libre > >
