Summary: Bitwidth Analysis with Application to Silicon Compilation
Mark Stephenson, Jonathan Babb, and Saman Amarasinghe
Massachusetts Institute of Technology
Laboratory for Computer Science
Cambridge, MA 02139
fmstephen,samang@lcs.mit.edu, jbabb@princeton.edu
Abstract
This paper introduces Bitwise, a compiler that minimizes
the bitwidth --- the number of bits used to represent each
operand --- for both integers and pointers in a program. By
propagating static information both forward and backward
in the program dataflow graph, Bitwise frees the program­
mer from declaring bitwidth invariants in cases where the
compiler can determine bitwidths automatically. Because
loop instructions comprise the bulk of dynamically executed
instructions, Bitwise incorporates sophisticated loop analy­
sis techniques for identifying bitwidths. We find a rich op­
portunity for bitwidth reduction in modern multimedia and
streaming application workloads. For new architectures that
support sub­word data­types, we expect that our bitwidth

Source: Amarasinghe, Saman - Computer Science and Artificial Intelligence Laboratory & Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology (MIT)

Collections: Computer Technologies and Information Sciences