------- Comment #7 from hjl dot tools at gmail dot com 2008-08-01 13:25 ------- (In reply to comment #6) > with -march=core2 it uses > > movd %xmm0, %rax > movq %rax, %xmm0 >
Even this isn't necessary. We should just use movq %xmm0,%xmm0 > with -march=opteron (and -march=generic) it uses > > movhps .LC0(%rip), %xmm0 > > ISTR there is some penalty for using movq on opteron? Opteron doesn't like inter-unit move, like movd %xmm0, %rax But it isn't necessary at all. We should use movq %xmm0,%xmm0 anyway. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=36992
