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Re: Pentium 4 Optimization Complimenting icc 5.0
- From: Joe Buck <jbuck at synopsys dot COM>
- To: rth at redhat dot com (Richard Henderson)
- Cc: jbuck at synopsys dot COM (Joe Buck), swalton at dsrnet dot com (Walton Shane),gcc at gnu dot org
- Date: Wed, 6 Feb 2002 17:17:43 -0800 (PST)
- Subject: Re: Pentium 4 Optimization Complimenting icc 5.0
On Wed, Feb 06, 2002 at 12:35:41PM -0800, Joe Buck wrote:
> > Intel has been attacked for this, by the way: the P4 often is slower than
> > the P3 for code tuned for the P3.
Richard Henderson writes:
> Not just "tuned for p3" -- the P4 is about 20% slower across the
> board when similar clock speeds are compared. The P4 architecture
> team inside Intel has taken quite a lot of heat for this.
... unless you can get all the pipelines set up just right with DSP-like
code with completely predictable control flow, in which case the P4 flies.