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RE: [patch] tuning gcc for Intel Core2
- From: "Menezes, Evandro" <evandro dot menezes at amd dot com>
- To: "Andi Kleen" <ak at suse dot de>, "Vladimir Makarov" <vmakarov at redhat dot com>
- Cc: gcc-patches at gcc dot gnu dot org
- Date: Mon, 13 Nov 2006 17:18:56 -0600
- Subject: RE: [patch] tuning gcc for Intel Core2
Andi,
> > +const int x86_accumulate_outgoing_args = m_ATHLON_K8 |
> m_CORE2 | m_PENT4 | m_NOCONA | m_PPRO | m_GENERIC;
> > +const int x86_prologue_using_move = m_ATHLON_K8 | m_PPRO |
> m_CORE2 | m_GENERIC;
> > +const int x86_epilogue_using_move = m_ATHLON_K8 | m_PPRO |
> m_CORE2 | m_GENERIC;
>
> Are you sure this is correct? Using moves in epilogue/prolgue
> generates much bigger code and AFAIK Core2 has special hardware
> to avoid any dependencies on the stack pointer, so shorter push/pop
> should be as fast here and use less icache.
With this option, GCC uses heuristics to figure out if the prolog and epilog take a significant time in the function and decides which one is best.
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Evandro Menezes AMD Austin, TX