use-def chains

Preston Briggs <>
Mon, 18 Sep 89 19:51:22 CDT

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use-def chains (Preston Briggs) (1989-09-18)
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Date: Mon, 18 Sep 89 19:51:22 CDT
From: Preston Briggs <>


I'm curious about how many people actually build
use-def chains for optimization.

(That is, for each variable reference, a list of all the instructions
  that might have set the variable. Alternatively, def-use chains
  link a definition with all the uses.)

They are mentioned often in the literature, but seem expensive in
time and space to build. On the other hand, Wegman and Zadeck (and
others) have been playing with a form called Static Single Assignment
(SSA) which seems reasonably space efficient. They also have methods
to construct the form quickly, at least for reducible flow graphs.

So, any experience out there? I'm especially interested in
space-efficient representations (think BIG fortran routines), so
ideas for compact representation are welcome too.

Preston Briggs

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