[llvm-commits] Patch for review: Speeding up ScheduleDAG computations

Roman Levenstein romix.llvm at googlemail.com
Thu Feb 28 06:15:44 PST 2008


I've implemented some improvements related to the computation of
heights, depths and priorities and latencies of SUnits.

The basic idea is that all these algorithms are computing the longest
paths from the root node or to the exit node. Therefore I changed the
existing implementation that uses and iterative and potentially
exponential algorithm to a well-known graph algorithm based on dynamic
programming. It has a linear run-time.

Tests on very big  input files with tens of thousends of instructions
in a BB, e.g. big4.bc use-case from Duraid's testsuit, indicate huge
speed-ups (up to 2x) compared to the current version,

Please review and tell if it is OK for submission.
- Roman
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