HyperLink   Speculative Execution Exception Recovery using Write-back Suppression.
   
Publication Year:
  1993
Authors
  Roger A. Bringmann, Scott A. Mahlke, Richard E. Hank, John C. Gyllenhaal, Wen-mei Hwu
   
Published:
  Proceedings of the 26th Annual ACM/IEEE Int'l Symposium on Microarchitecture, Austin, Texas, pp. 214-223, Dec. 1993
   
Abstract:

Compiler-controlled speculative execution has been shown to be effective in increasing the available instruction level parallelism (ILP) found in non-numeric programs. An important problem with compiler-controlled speculative execution is to accurately report and handle exceptions caused by speculatively executed instructions. Previous solutions to this problem incur either excessive hardware overhead or extra register pressure. This paper introduces a new architecture scheme referred to as write-back suppression. This scheme systematically suppresses register file updates for subsequent speculative instruction. We show that with a modest amount of hardware, write-back suppression. This scheme systematically suppresses register file updates for subsequent speculative instructions after an exception condition is detected for a speculatively executed instruction. We show that with a modest amount of hardware, write-back suppression supports accurate reporting and handling of exceptions for compiler-controlled speculative execution without adding to the register pressure. Experiments based on a prototype compiler implementation and hardware simulation indicate that ensuring accurate handling of exceptions with write-back suppression incurs very little run-time performance overhead.