Code Movement Method Based on Complementary Predicates

Abstract

The invention relates to a code moving method based on complementary predicates. The method includes the steps that whether the predicate condition from commands of a current node to target nodes is satisfied or not is judged; the target nodes are forerunner nodes or successor nodes, the nodes are code snippets of an assembling file, and no loop exists among the nodes; when the predicate condition is satisfied, a deduction register of the current node is modified according to the predicate condition; the commands which are determined to be moved in the current node are copied to the target codes in a control flow graph, and the commands in the current node are deleted; a data dependence graph is repaired. By the combination of complementary predicate structures of the predicates, code copy is restrained by modifying the deduction register of the commands in the code moving process without code compensation, and the code moving method is low in implementation cost, easy to realize, and high in engineering realizing value.

Description

technical field [0001] The invention relates to code movement technology, in particular to a code movement method based on complementary predicates. Background technique [0002] Global code movement is divided into looped scheduling and acyclic scheduling. Cyclic scheduling is to move schedulable instructions across basic blocks along the back edge (Back Edge) that leads to loops in the control flow graph, and the moving area usually only occurs within the loop segment, as proposed by M Tokoro et al. Modular Scheduling. Acyclic scheduling only deals with subpath fragments or cyclic subfragments in the control flow graph that do not have loops. [0003] Existing technical solutions are generally proposed for scheduling algorithms, among which more representative algorithms include trace scheduling algorithm, seepage scheduling algorithm, global scheduling algorithm, and wave-edge scheduling algorithm. in: [0004] Trace Scheduling algorithm (Trace Scheduling) is proposed...

AI Technical Summary

Problems solved by technology

[0007] Wavefront Scheduling algorithm (Wavefront Scheduling) was proposed by Bharadwaj et al. It is very flexible. It efficiently completes code compensation by eliminating JS edges or critical edges and inserting Interface Blocks. However, its implementation process is very Complex, currently only used by ecc compilers

[0008] Existing technologies are for intermediate language level applications when the compiler backend registers have not been allocated, they do not combine the speculative execution technology in the VLIW architecture to achieve code movement

Images