A Vectorizing Compiler for Multimedia Extension

International Journal of Parallel Programming
vol. 28, no. 4, pp. 363--400, August 2000

Authors

1. N. Sreraman, Department of Computer Science and Automation
2. R. Govindarajan, Supercomputer Education and Research Centre; Department of Computer Science and Automation

Abstract

In this paper, we present an implementation of a vectorizing C compiler for Intel's MMX (Multimedia Extension). This compiler would identify data parallel sections of the code using scalar and array dependence analysis. To enhance the scope for application of the subword semantics, our compiler performs several code transformations. These include strip mining, scalar expansion, grouping and reduction, loop fission and distribution. Thereafter inline assembly instructions corresponding to the data parallel sections are generated. We have used the Stanford University Intermediate Format (SUIF), a public domain compiler tool, for our implementation.

We evaluated the performance of the code generated by our compiler for a number of benchmarks. Initial performance results reveal that our compiler generated code produces a reasonable performance improvement (speedup of 2 to 6.5) over the the code generated without the vectorizing transformations/inline assembly. In certain cases, the performance of the compiler generated code is within 85% of the hand-tuned code for MMX architecture.

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