Optimization techniques and applications with examples introduces the fundamentals of all the commonly used techniques in optimization that encompass the broadness and diversity of the methods traditional and new and algorithms. They provide compile time information, such as the intermediate representation ir and analysis information, of each compilation unit along with an object. Note that the slope of this function is equal to 2 and is constant over the entire range of x values. Hence, a number of methods have been developed for solving di. Interprocedural usedefinition chains are defined analogously in terms of interprocedural reaching definitions. Understanding the difference between them is the first step in understanding how the different levels, settings, and techniques can increase performance. Code optimization in compiler design pdf compiler design code optimization optimization is a program transformation technique, which tries to improve the code by making it consume less resources. Techniques, such as aggressive inlining and interprocedural optimization, have been developed to alleviate this problem, but, due to code growth and compile time issues, these can be applied only sparingly.
Interprocedural analysis is a mechanism for performing optimization across function boundaries. Lecture notes optimization methods sloan school of. Interprocedural analysis colorado state university. The highlevel general programming constructs are replaced by the lowlevel programming codes in optimization codes. A framework for interprocedural optimization in the presence. Interprocedural optimization ipo is a collection of compiler techniques used in computer. Interprocedural optimization wikipedia a program transformation technique used for improving the code by enabling it to consume fewer resources and deliver high speed is known as optimization. Automatic parallelization and optimization for irregular scienti.
The optimizing translator performs interprocedural analysis, but only within a compilation unit. Distinguishing between optimization and tuning you can use optimization and tuning separately or in combination to increase the performance of your application. Peephole optimization in compiler design geeksforgeeks. An optimization algorithm is a procedure which is executed iteratively by comparing various solutions till an optimum or a satisfactory solution is found. To alleviate the inconvenient optimization scope of individual procedures, most modern compilers employ interprocedural optimization andor aggressive inlining.
The computation of interprocedural definitionuse chains requires tracking the uses of global variables and formal and actual reference parameters that can be reached across call and return sites i. Interprocedural pointer analysis for c rice university. Interprocedural optimization ipo is a collection of compiler techniques used in computer programming to improve performance in programs containing many frequently used functions of small or medium length. Interprocedural optimization is a collection of compiler techniques used in computer programming to improve performance in programs containing many frequently used functions of small or medium length. Pdf empirical study of optimization techniques for massive.
Interprocedural optimizations for improving data cache. Cs553 lecture interprocedural analysis 5 interprocedural analysis vs. Characteristics, scope, development of or in india, role of computers in or. Optimization techniques are a powerful set of tools that are important in efficiently managing an enterprises resources and thereby maximizing shareholder wealth. The actual computation is interrupted at the call and resumed when the called procedure has terminated. Interprocedural analysis an overview sciencedirect topics. Web chapter a optimization techniques 9 which is graphed in figure a. The utility of the resulting information was investigated using an optimizing pascal compiler. This optimization can substantially increase performance if the application has constants passed to functions. Optimization techniques pdf notes 2019 all tricks here. This dissertation examines how to implement an interprocedural.
Effective interprocedural optimization of objectoriented. Many of the optimizations are only relevant for large functions small functions are inlined into the caller. Interprocedural analysis and optimization, communications. Automatic parallelization and optimization for irregular. Runtime invalidation and recompilation mechanisms can be expensive in both space and time, and, therefore, generally restrict optimization. Interprocedural analysis gathering information about the whole program instead of a single procedure examples. Interprocedural analysis useless for code optimization s. In this chapter different types of optimization techniques are described briefly with emphasis on those that are used in the present dissertation. What interprocedural optimization techniques are worth consideration, and when is one. Compiling programs for concurrency, scalability, locality, and energy ef. These techniques include communication cost reduction for irregular loop partitioning, interprocedural optimization techniques for communication preprocessing when the irregular code has the procedure call, global vs. A framework for unrestricted wholeprogram optimization liberty.
Nature and meaning, history, management applications, modeling. While efficient new algorithms for interprocedural dataflow analysis have made these techniques practical for use in production compilation systems,a new. Barth extended spillmans technique, requiring multiple passes over the. Optimize options using the gnu compiler collection gcc.
In this chapter, we extend our programming language by procedures. Here you can download the free lecture notes of optimization techniques pdf notes. This post lists the interprocedural optimizations implemented in gcc 7. Fast and highly optimizing separate compilation for. The major optimization highlights provided by the visualage compiler are. Interprocedural optimization interprocedural analysis gather information across multiple procedures typically across the entire program can use this information to improve intraprocedural analyses and optimization e. This classification is then used to extend the common subexpression elimination, dead code elimination, and invariant hoisting optimizations to. Chapter 4 optimization techniques in perspective optimization means maximization or minimization of one or more functions with any possible constraints. Interprocedural data flow analysis in soot using value contexts. The impact of interprocedural analysis and optimization on. Applying the power function rule to this example, where a 2 and b 1, yields 2 note that any variable to the zero power, e. It can sometimes make sense to perform interprocedural analyses within an intermediate level, such as a library or a java package. Interprocedural optimization is not used extensively due to cost. This paper demonstrates that interprocedural optimization yields significant performance benefits.
Few commercial optimizing compilers employ interprocedural techniques because the cost of gathering the requisite information in a traditional compiler is too great. Abstract an interprocedural analysis is precise if it is. This information is difficult to produce for programs written with pointerbased languages such as c. These results were also compared with interprocedural modref analysis. Link time optimization lto has been used to employ interprocedural analysis and restructuring techniques across multiple compilation units 1, 2, 5, 12. Interprocedural symbolic range propagation for optimizing compilers. Gather information across multiple procedures typically across the entire program. Optimum seeking methods are also known as mathematical programming techniques, which are a branch of operations research. Enhancing compiler techniques for memory energy optimizations by joseph anthony zambreno a thesis submitted in partial fulfillment of the requirements for the degree of master of science northwestern university evanston, illinois june 2002.
Interprocedural symbolic range propagation for optimizing. Many powerful code optimization techniques rely on accurate information connecting the definitions and uses of values in a program. Empirical study of optimization techniques for massive slicing david binkley, loyola college in maryland mark harman, kings college london and jens krinke, fernuniversit. Efficient computation of interprocedural definitionuse chains. Both of these systems implement recompilation analysis using techniques described in this paper. A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. If set to true, enables interprocedural optimizations if they are known to be supported by the compiler. Interprocedural optimization interprocedural analysis gather information across multiple procedures typically across the entire program use this information to improve intraprocedural analyses and optimization e. Ipo seeks to reduce or eliminate duplicate calculations, inefficient use of memory, and to simplify iterative sequences such as lo.
Interprocedural analysis that is performed by the ipa compiler option improves on the limited interprocedural analysis described above. Introduction it is expected that future computer systems will comprise of massively multicore processors with hundreds of cores per chip. Often prevents it from making optimizations when would only affect behavior under. One of the primary goals of the ir n programming environment project is to mount a concerted attack on the problems of performing interprocedural analysis and optimization in a compiler.
Thereis nosingle method available for solving all optimization problemse. Five optimization levels with multiple related options or suboptions. Similarly, the presence of a cali within a loop can. While efficient new algorithms for interprocedural dataflow analysis have made these techniques practical for use in production compilation systems,a new problem has arisen. To address these drawbacks, we propose a new framework, called the extant analysis framework, for interprocedural. Interprocedural data flow analysis in soot using value. A framework for unrestricted wholeprogram optimization.
While some techniques in this section are active at advanced optimization levels, certain types of applications can receive a performance benefit even when you apply only basic optimizations. Such an interprocedural optimization can make the program run three times faster than when optimized without interprocedural analysis. In optimizing data cache behavior of arrayintensive applications, two different techniques have emerged. Csltr87342 november 1987 computer systems laboratory department of electrical engineering stanford university stanford, ca 94305 abstract the problem of tracking data flow across procedure boundaries has a lonhistory of theoretical. Pragmas provide the compiler with the instructions for specific tasks, such as splitting large loops into smaller ones, enabling or disabling optimization for code, or offloading computation to the target. A classification is presented that encapsulates a subprograms sideeffects into a single attribute. Optimizing procedure calls inlining whatwhere to inline. Unfortunately, interprocedural optimization directly conflicts with one of. An interprocedural optimization strategy can, on the other hand, see the big picture and select the most suitable programwide memory layout without resorting to dynamic layout transformation.
May 30, 2017 the obvious case is inlining, but there are many more cases. While efficient new algorithms for interprocedural data flow analysis have made these techniques practical for use in production compilation systems, a new problem has arisen. Peephole optimization is a type of code optimization performed on a small part of the code. Managing interprocedural optimization semantic scholar.
Thispaper introduces the procedure boundary eliminationpbe compilation framework, which allows unrestricted wholeprogram optimization. This paper focuses on compiler techniques to address. In optimization of a design, the design objective could be simply to minimize the cost of production or to maximize the efficiency of production. Interprocedural analysis useless for code optimization. Interprocedural analysis ipa interprocedural analysis ipa can analyze and optimize your application as a whole, rather than on a filebyfile basis. Interprocedural strength reduction of critical sections in. This optimization analyzes the program to determine when values passed to functions are constants and then optimizes accordingly. In each of these areas, the goal is to improve the efficiency of code generated for a whole program by giving the compiler more context over which to optimize. These details are probably not carefully explained in the compiler manual, and if they are, they will likely be passed over as being not relevant to the. Thus, optimization can be taken to be minimization. Can use this information to improve intraprocedural analyses and optimization e. Although frequent procedure calls and message sends are important structuring techniques in objectoriented languages, they can also severely degrade application runtime performance. March 4, 2015 interprocedural analysis 5 interprocedural analysis vs.
This dissertation demonstrates that interprocedural analysis can be both practical and effective for sizeable objectoriented programs. A new optimization, register promotion, that was specifically designed to use the information generated by pointer analysis was also developed. Interprocedural optimization ipo is an automatic, multistep process that allows the compiler to analyze your code to determine where you can benefit from specific optimizations. Interprocedural optimization refers to program transformations that involve more than. Interprocedural analysis gathering information about the whole program instead of a single procedure interprocedural optimization program transformation that involves more than one procedure in the program uses interprocedural analysis tuesday, may 4, 2010.
We also show that the analyzer can speed up the execution times of the rest our optimizer. Find materials for this course in the pages linked along the left. Finally, related optimization techniques of possibly greater potential are. It is performed on the very small set of instructions in a segment of code. If interprocedural analysis ipa can determine that the call to sub does not alter gv, the address calculation inside the loop can be significantly optimized. The body of the procedure often forms a new scope for local names, i. When you use ipo options along with the x or ax linux os options, or the qx or qax windows os options, you may see additional optimizations for intel. Interprocedural analysis extend intraprocedural analyses to work across calls doesnt increase code size but, doesnt eliminate direct runtime costs of call and it may not be as effective as inlining at cutting the precision cost of procedure calls.
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