BitValue Inference: Detecting and Exploiting Narrow Bitwidth Computations
CARNEGIE-MELLON UNIV PITTSBURGH PA SCHOOL OF COMPUTER SCIENCE
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The authors present a compiler algorithm called BitValue, which can discover unused and constant bits in dusty-deck C programs. BitValue uses forward and backward dataflow analyses, generalizing constant-folding and dead-code detection at the bit-level. This algorithm enables compiler optimizations targeting special processor architectures for computing on non-standard bitwidths. Using this algorithm, they show that up to 36 of the computed bytes are thrown away. Also, they show that on average 26.8 of the values computed require 16 bits or less for programs from SpecINT95 and Mediabench. A compiler for reconfigurable hardware uses this algorithm to achieve substantial reductions up to 20-fold in the size of the synthesized circuits.
- Numerical Mathematics
- Computer Programming and Software