Hello,
> _mm_hadd_pd is a sse3 intrinsic so you have to pass -msse3 to allow > GCC to use it. However, this will cause a SIGILL on any amd64/i386 > processor without sse3 so instead the code should be replaced with > something more portable. Actually, the compile command defines -D__SSE3, and the according headers are only included if this define is set. I've tried to add a patch that removes the according tests in the CMakeLists.txt, but then I got /home/gerddie/debian-med/iqtree/phylokernel.h:19:2: error: #error "You must compile with SSE3 enabled!" within a function that does a so called horizontal add. I'll think of a patch to emulate the according code with sse2 instructions. Best, Gert