PLDI '92 Proceedings of the ACM SIGPLAN 1992 conference on Programming language design and implementation
The power of assignment motion
PLDI '95 Proceedings of the ACM SIGPLAN 1995 conference on Programming language design and implementation
Complete removal of redundant expressions
PLDI '98 Proceedings of the ACM SIGPLAN 1998 conference on Programming language design and implementation
ABCD: eliminating array bounds checks on demand
PLDI '00 Proceedings of the ACM SIGPLAN 2000 conference on Programming language design and implementation
Global optimization by suppression of partial redundancies
Communications of the ACM
Effective null pointer check elimination utilizing hardware trap
ASPLOS IX Proceedings of the ninth international conference on Architectural support for programming languages and operating systems
Java Virtual Machine Specification
Java Virtual Machine Specification
The Java Language Specification
The Java Language Specification
Optimal and efficient speculation-based partial redundancy elimination
Proceedings of the international symposium on Code generation and optimization: feedback-directed and runtime optimization
Partial Redundancy Elimination Driven by a Cost-Benefit Analysis
ICCSSE '97 Proceedings of the 8th Israeli Conference on Computer-Based Systems and Software Engineering
Automatically Reducing Repetitive Synchronization with a Just-in-Time Compiler for Java
Proceedings of the international symposium on Code generation and optimization
Sentinel PRE: Hoisting beyond Exception Dependency with Dynamic Deoptimization
Proceedings of the international symposium on Code generation and optimization
Experiences with Multi-threading and Dynamic Class Loading in a Java Just-In-Time Compiler
Proceedings of the International Symposium on Code Generation and Optimization
The DaCapo benchmarks: java benchmarking development and analysis
Proceedings of the 21st annual ACM SIGPLAN conference on Object-oriented programming systems, languages, and applications
Local redundant polymorphism query elimination
Proceedings of the 8th International Conference on the Principles and Practice of Programming in Java
An intermediate representation for speculative optimizations in a dynamic compiler
Proceedings of the 7th ACM workshop on Virtual machines and intermediate languages
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Partial redundancy elimination aims to reduce the number of times an expression is computed more than once. The traditional Lazy Code Motion (LCM) algorithm formulated by Knoop, Ruthing and Steffen, through its reliance on unordered bit vectors, is severely limited in its ability to remove redundancy when precise exception semantics are required because bit vectors cannot express the order of exception checks. This paper describes our new PRE algorithm Exception Check Motion that uses the LCM algorithm to treat and optimize exception checks in a similar way to any other expression. Unlike earlier techniques that can remove only the compare instruction of a partially redundant exception check, our solution can eliminate both the compare and trap instructions without any run time code patching or expensive recovery operations. Since it is the trap instructions that restrict subsequent code motions, our technique gives downstream optimizations more flexibility to improve the performance of the resulting code once the partially redundant checks are eliminated. Our analysis has been implemented in the IBM® Testarossa (TR) just-in-time (JIT) compiler in the IBM Developer Kit for Java Release 5.0 as part of the J9 Virtual Machine. We measure performance improvements up to 7.6% and averaging 2.5% across 22 SPEC and DaCapo benchmarks on 4-way IBM pSeries (PowerPC) hardware.