Compiling for Alpha

DEC's Alpha Architecture Handbook (available at 1-800-332-2717) has some
material of interest to compiler writers.


I don't want to type in all of Appendix A, but I'll give one example of
their comments:


If an if-then-else construct has an execution profile skewed slightly from
50-50 (51-49 is enough) then the correct code sequence involves a single
conditional branch which normally falls through into the likeliest arm.
Branch-taken should go to the less-likely arm, which should terminate in
an unconditional-branch back to the procedure mainline.


This may seem a bit low-level, but they give reasons for several of their
rules, and most of the suggestions sound like they apply to other machines
as well.
--
Don D.C.Lindsay Carnegie Mellon Computer Science
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