DM-SIMD:A New SIMD Predication Mechanism for Ezploiting Superword Level Parallelism
Predication mechanism is a promising architectural feature for exploiting superword level parallelism (SLP) in presence of control flow However,for the sake of binary compatibility,current sIMD extension only supports partial predicated execution such as select method which has performance and safety problems.In this paper,we present a new SIMD predication mechanism,data masked sIMD (DM-SIMD),capable of supporting full predication without touching existing ISA.DM-SIMD avoids the high encoding overhead of traditional full predication,and eliminates safety problem raised by partial predication as well. The cornerstone of this mechanism is the state change idea which adds new instructions to set internal state in S1MD datapath rather than putting the VM setting bits in every SIMD instruction. To effectively use DM-SIMD facilities for sIMD code generation,the compilation strategies are also proposed. We implemented these techniques in a vectorizing compiler and experiments were conducted on various kinds of applications. The results show that performance speedup,about 20% higher than current SIMD extensions,can be achieved.
control flow SIMD full predication SLP
Libo Huang Li Shen Sheng Ma Nong Xiao Zhiying Wang
School of Computer,National University of Defense Technology,Changsha,China,410073
国际会议
2009 IEEE 8th International Conference on ASIC(第八届IEEE国际专用集成电路大会)
长沙
英文
863-866
2009-10-20（万方平台首次上网日期，不代表论文的发表时间）