Decoupled value prediction on trace processors

Value prediction is a technique that breaks true data dependences by predicting the outcome of an instruction, and executes speculatively its data-dependent instructions based on the predicted outcome. In this paper, we address several implementation issues for value prediction which are important on wide-issue superscalar architectures, and present a value prediction scheme based on the trace processor. The scheme decouples the value prediction from the instruction fetch stage and uses a hybrid predictor with dynamic classification. We use execution-driven simulation to study the performance of such a scheme using SPECint95 benchmarks