PPD - A PRACTICAL PARALLEL LOOP DETECTOR FOR PARALLELIZING COMPILERS ON MULTIPROCESSOR SYSTEMS

It is well known that extracting parallel loops plays a significant ro le in designing parallelizing compilers. The execution efficiency of a loop is enhanced when the loop can be executed in parallel or partial parallel, like a DOALL or DOACROSS loop. This paper reports on the pr actical parallelism detector (PPD) that is implemented in PFPC (a port able FORTRAN parallelizing compiler running on OSF/1) at NCTU to conce ntrate on finding the parallelism available in loops. The PPD can extr act the potential DOALL and DOACROSS loops in a program by invoking a combination of the ZIV test and the I test for verifying array subscri pts. Furthermore, if DOACROSS loops are available, an optimization of synchronization statement is made. Experimental results show that PPD is more reliable and accurate than previous approaches.