Thinking Machines Corporation

Tobias M Weinberg

Alexander D Vasilevsky

Lisa A Tennies

Clifford A Lasser

Linda J Seamonson

Gary W Sabot

A software compiler having a code generator and a scheduler. The code generator transforms a lowered intermediate representation (IR) of a source computer program, written in a known computer language, to an assembly language program written in a non-standard instruction set. In particular, the code generator translates vector instructions in the lowered IR to vector instructions from the non-standard instruction set. The vector instructions from the non-standard instruction set are defined such that assembly language programs written with them do not suffer from the effects of pipeline delays. Therefore, according to the present invention, the code generator eliminates the effects of pipeline delays when transforming the lowered IR to the assembly language program. Since the code generator eliminates the effects of pipeline delay, the scheduler's task is greatly simplified since the scheduler need only maximize the use of the functional units.

Compiling a source code vector instruction by generating a subgrid loop

The present invention provides a parallel vector machine model for building a compiler that exploits three different levels of parallelism found in a variety of parallel processing machines, and in particular, the Connection Machine.RTM. Computer CM-2 system. The fundamental idea behind the parallel vector machine model is to have a target machine that has a collection of thousands of vector processors each with its own interface to memory. Thus allowing a fine-grained array-based source program to be mapped onto a course-grained hardware made up of the vector processors. In the parallel vector machine model used by CM Fortran 1.0, the FPUs, their registers, and the memory hiearchy are directly exposed to the compiler. Thus, the CM-2 target machine is not 64K simple bit-serial processors. Rather, the target is a machine containing 2K PEs (processing elements), where each PE is both superpipelined and superscalar. The compiler uses data distribution to spread the problem out among the 2K processors. A new compiler phase is used to separate the code that runs on the two types of processors in the CM-2; the parallel PEs, which execute a new RISC-like instruction set called PEAC, and the scalar front end processor, which executes SPARC or VAX assembler code. The pipelines in PEs are filled by using vector processing techniques along the PEAC instruction set. A scheduler overlaps the execution of a number of RISC operations.

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Somerville, MA, United States of America

Tobias M Weinberg