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Re: Register Allocation
On Tuesday 22 November 2005 20:26, Peter Bergner wrote:
> Insn Annotations [page(s) 17-18]:
> * I like the idea of easy access to the register usage info
> provided by the insn annotations. RTL isn't really setup
> for making that easy.
But it is if you use df.c. Really, it is. It is right there:
reg-use and reg-def chains per insn, UD and DU chains, etc.
> Spill Cost Engine [page(s) 26-29]:
> * The register allocator should not be estimating the execution
> frequency of a basic block as 10^nesting level. That information
> should be coming from the cfg which comes from profile data or
> from a good static profile.
The profile information or branch predictions are available in the
CFG. In fact, even the current Chow-like allocator uses it. See
allocno_compare in global.c.
Gr.
Steven