Constraint analysis for DSP code generation

Constraint analysis for DSP code generation

“…Our implementation on a HP 9000/735 has been tested on the inner loops from 4 different real life industrial examples [Mesm98,Mesm99a]. The results are shown in Table 4.1.…”

“…The way resource constraints are analysed is discussed in Section 3.5. In Section 3.6 the analysis is integrated with scheduling, which comprises our approach for scheduling with resource constraints [Mesm97a]. In Section 3.8 the complexity of this approach is discussed, and Section 3.9 shows some experimental results.…”

“…The pruning rule resulting from Lemma 3.2 has been implemented and integrated in the FACTS code generation environment [Eijk00], [Mesm01]. In this section the pruning rules are used in an approach to solve the problem of scheduling with precedence and resource constraints.…”

“…Using constraint analysis, a scheduler is guided rather than hampered by these constraints: By using the constraints to prune the schedule search space, the scheduler is often prevented from making a decision that inevitably violates one or more constraints. Some of these techniques have been integrated in the research code generation tool FACTS [Eijk00], [Mesm01] together with some techniques following the same philosophy like execution interval analysis [Timm95] and symmetry analysis [Eijk99].…”

Identification and exploitation of symmetries in DSP algorithms

“…We will now explain how this transformation can be used to impose extra constraints on the DFG without excluding all feasible schedules. These constraints take the form of sequence edges between operations [8]. A sequence edge from an operation u to an operation v with integer weight w expresses the constraint that operation u should start at least w cycles before operation v. This means that any feasible schedule ö has to satisfy: ö(v) w ö(u) ) w. The techniques proposed in this paper break the symmetry in a DFG by introducing sequence edges with weight zero between symmetric operations.…”