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Re: Comparison of Itanium gcc 4.1 and 4.2 on Spec2000
On Fri, Feb 23, 2007 at 11:09:29AM -0500, Vladimir N. Makarov wrote:
> Yes, that is the current state of 4.1 and 4.2 branches (as of
> yesterday). I don't think we will see a change with the reverted
> alaising patches for itanium because conservative aliasing most probably
> will be compensated by itanium hardware (itanium speculation insn
> support was added for 4.2).
Perhaps I'm missing something obvious, but often conservative aliasing
results in reading lots of extra data from memory. How can speculation
compensate for that? It seems that the best you can do is reduce the
penalty, if you can do something in parallel with the extra I/O.