Oh I've made an error. It should work if you replace the code by :
{$ifdef CPUI386}
UseSSE := is_sse_cpu and FLAG_ENABLED_SSE;
if UseSSE then
begin
UseSSE2 := is_sse2_cpu;
UseSSE3 := sse3_support
end
else
{$endif}
begin
UseSSE := false;
UseSSE2 := false;
UseSSE3 := false;
end;
By the way, maybe SSE support could be added to 64 processors too.