Hi, there's something I don't understand about intel compiler on my linux x64 platform...I'm quite lost in cpu architectures/instruction sets, so the answer is probably simple, it's just that I can't find it anywhere written explicitly.
I installed Free Intel compiler 10.1 for Linux (distribution which is marked as Intel64) on my Ubuntu 7.10 x86_x64 system(Core2Duo cpu).
I have a piece of code that works intensively with 64-bit integers, so I would expect big speedup on a 64bit system.
When i compiled the source with -O2(no other parameters), i found out that the performance is indeed good, but what made me wonder was that even if I set pentium3 as target(with march=pentium3 and pentium3 is clearly having no 64bit instruction set support), the performance stays roughly the same. My conclusion: compiler is still generating IA32 code, perhaps with some sse and vectorization stuff which speeds things up. But if I'm right, how can I generate 64-bit code?
Thanks for any advice ;)
And Happy New Year btw.