Dosingle Loop

• Represents single assignment statement
• Each variable assigned must be indexed by all loop index variables
• Each element must be assigned only once
• A statement in a dosingle sees all the updates
  • From previous or subsequent iterations
  • From previous or subsequent statements

dosingle i = 1 to 4 do a[i] = a[i-1] + 1 b[i] = b[i+1] + a[i-1] enddo

Summary

• Re-structure code to exploit pipeline and caches.
• Convert sequential loops involving scalars to vector operation.
• Convert sequential loops into parallel loops.
• Partition data for data parallel model.
• Minimize messages to reduce overheads.

Control Flow Analysis

• Shows hierarchical flow of control
• Source control flow is not available in MIR or LIR
• Loops may be constructed of ifs and gotos