Compilation Methods SS 2009 - Slide 502
Objectives:
DDG exhibits parallelism
In the lecture:
- Show where sequential code is overspecified.
- Derive reordered sequences from the ddg.
- single assignment for ti: ti contains exactly one value; ti is not reused for other values.
- Without that assumption further dependencies have to manifest the order of assignments to those registers.
Suggested reading:
Kastens / Übersetzerbau, Section 8.5, Abb. 8.5-1
Assignments:
- Write the operations of the basic block in a different order, such that the effect is not changed and the same DDG is produced.
Questions:
- Why does this example have so much freedom for rearranging operations?
- Why are further dependences necessary if registers are allocated?
©2009 Prof. Dr. Uwe Kastens
Generiert mit Camelot | Probleme mit Camelot? | Geändert am: 30.03.2009