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Topic: Compiler optimization

Related Topics

Optimization (computer science)

Constant propagation

Common subexpression elimination

Rematerialization

Instruction scheduling

Control flow graph

Compiler

Code generation

Static single assignment form

Loop nest optimization

Dead code elimination

Intermediate language generation

Incremental compiler

Constant folding

Jump threading

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	Creating High Performance Embedded Applications Through Compiler Optimizations
		After the perfect compiler optimization has been applied or the most efficient algorithm has been implemented, it is important to verify the results.
		However, good compiler vendors put enough time and energy into ensuring that their compiler is the best that they want to be able to share their expertise.
		Some compilers have processor specific optimizations that provide hints to the compiler about what processor the application is going to be run on.
	www.intel.com /technology/magazine/computing/compiler-optimization-0305.htm (2675 words)

	Compiler Optimization
		There are also some optimizations that you might not choose to use for your specific application.
		Optimizing for space can actually be faster than optimizing for speed because programs optimized for speed are almost always larger, and therefore more likely to cause additional paging than programs optimized for space.
		option instructs the compiler not to track unwindable objects as it normally would in case an exception is thrown and objects must be unwound on the stack.
	www.tantalon.com /pete/cppopt/compiler.htm (1000 words)

	[No title]
		If you don't wish to run software on other machines other than your own, you might want to change the default compiler options so that they will be compiled with a higher optimization level, and generate code for your specific architecture.
		Compilers are very sensitive to certain hardware too.
		Bad memory can cause compilation problems when a high level of optimization is used, like the -O3 setting.
	www.linuxfromscratch.org /hints/downloads/files/optimization.txt (859 words)

	Insecure Compiler Optimization - OWASP
		The source code is compiled using an optimizing compiler, which identifies and removes the function that overwrites the contents as a dead store because the memory is not used subsequently.
		In the example, the compiler interprets the call to memset() as dead code because the memory being written to is not subsequently used, despite the fact that there is clearly a security motivation for the operation to occur.
		The problem here is that many compilers, and in fact many programming languages, do not take this and other security concerns into consideration in their efforts to improve efficiency.
	www.owasp.org /index.php/Insecure_Compiler_Optimization (373 words)

	Advanced Compiler Optimization Techniques
		However, of greater importance is a compiler's ability to completely ignore the operation of the function on static variables or registers used by the error handler to improve optimization of the code around the call point.
		The Diab compiler will generate a bc+ instruction for the conditional branch instruction indicating that the forward branch is predicted to be taken rather than the default not taken as the regular bc instruction would indicate.
		Although such optimizations have usually been associated with the code selection and code generation phases, to be truly effective each optimization phase must have an intimate knowledge of the target architecture.
	www.embedded.com /shared/printableArticle.jhtml?articleID=192200575 (3901 words)

	Code Optimization Using the GNU C Compiler LG #71
		If the compiler is an optimizing compiler, one of these stages "optimizes" the machine language code so that it either takes less time to run or occupies less memory or sometimes both.
		The GNU C Compiler is a sophisticated optimizing C compiler that uses a large array of optimization techniques to produce efficient code.
		From these optimization techniques and the various pieces of information that are required to apply them, the reader can appreciate the type of sophisticated and complex analysis that the compiler must carry out on the program.
	www.tldp.org /LDP/LG/issue71/joshi.html (2868 words)

	Compiler optimization
		Stony Brook compilers do not perform algorithm register parameterpassing because the IA-32 architecture is too strange to allow this without needingto shuffle these algorithm parameters to a proper area, such as another registeror on to the stack, based on the register needs of the procedure in question.
		The compiler generates procedure stubs that will allow both stackbased and register based cases to work, but more code will be linked into the applicationif the definitions are referred to before the implementation is compiled.
		The reason for using the LIB compiler option, and therefore enablesmart linking, is to be able not link in all of the non register parameter pass procedurestubs that are not referenced, because in a reasonable situation none of these shouldever be called, or at least only a very small few.
	www.modula2.org /sb/websitearchive/env/index573.htm (753 words)

	University of Alberta CMPUT680
		A successful compiler optimization must produce a faster program, result in moderate compilation time and moderate use of storage - both for the final machine code and during the compilation process.
		Although compiler design and optimization is a research discipline on its own right, understanding compiler optimization is very important for architecture and system research.
		Such optimizations are often language independent and explore the relationship between compiler optimization and architecture and system design.
	www.cs.ualberta.ca /~amaral/courses/680 (1012 words)

	Creating High Performance Embedded Applications Through Compiler Optimizations
		After the perfect compiler optimization has been applied or the most efficient algorithm has been implemented, it is important to verify the results.
		However, good compiler vendors put enough time and energy into ensuring that their compiler is the best that they want to be able to share their expertise.
		Some compilers have processor specific optimizations that provide hints to the compiler about what processor the application is going to be run on.
	developer.intel.com /technology/magazine/computing/compiler-optimization-0305.htm (2685 words)

	Compiler Optimization Of MechAssault 2
		But by changing our compiler optimization settings, we also squeezed out a significant performance gain--nearly 10%--that was basically free.
		If you enable exception handling, the compiler will build a look-up table for your entire program indicating what local objects need to be destroyed at any point of any function, if an exception occurs at that point.
		Because the compiler cannot know that the locations are distinct, it may be forced to write a register value back to memory, then re-read another memory location for another compiler access.
	gamearchitect.net /Articles/CompilerOptimizationOfMA2.html (1038 words)

	Galaxy Design Platform
		The concurrent optimization engines spend this savings to minimize power consumption, reduce area, lower test costs or increase yield.
		Synopsys’ IC Compiler tool is a next-generation place-and-route system that provides all the functionality necessary for high-quality physical design including floorplanning, physical synthesis, placement, routing, timing, signal integrity (SI) optimization, power reduction, design-for-test (DFT), and yield optimization.
		The unified CCS model for timing, noise and power, extends the analysis and optimization capabilities within the Galaxy Design Platform to concurrently address nanometer effects and thereby reduce design margins and minimizing iterations.
	www.synopsys.com /products/solutions/galaxy_platform.html (864 words)

	IBM - XL C/C++ - Features and benefits
		The -qlanglvl compiler option is enhanced to support all of the available language levels that you can use to compile your code.
		Compiler options, directives, and pragmas offer programmers a number of ways to optimize their code.
		XL C/C++ can optimize code to take advantage of PowerPC technology found in the BladeCenter JS20 and JS21, Blue Gene, System p, and System i platforms from IBM. The -qarch and -qtune suboptions let you instruct the compiler to generate code optimized for your chosen target processor or processor family.
	www.ibm.com /software/awdtools/xlcpp/features (777 words)

	HI-TECH Software Forums: Compiler Optimization
		We feel that the optimization option provided in the IDE is not working.
		Even though we enable or disable optimization with the highest level (9), no changes in the flash code size / RAM size is seen.
		Our compilers before version 9 defaulted to no optimization, and our existing MPLAB plugin only adds an optimization option to the command line it generates when optimization is turned on.
	www.htsoft.com /forum/all/showthreaded.php?Cat=0&Number=22978&page=&fpart=&vc= (161 words)

	Massively parallel compiler optimization
		When conventional compilation is completed, the processors that were given sections to optimize can be polled for the best optimization found so far, and the optimizations can be collected as a final pass.
		The user might supply a time constraint on compilation, so the search for reduced operation counts can be limited by the user's patience instead of the completion of conventional compilation.
		We tried to optimize the core of the computation given by the statement inside the loops, which, after a convenient renaming of the variables, is
	www.scl.ameslab.gov /Publications/Gus/FiveMultiplications/node15.html (604 words)

	Compiler Optimization
		compiles into bytecodes that execute literally, meaning 10 is pushed on the stack, stored in local var 0, etc. A good C compiler would optimize this code (assuming x and y are not used elsewhere in the method) to simply store 30 in local var z.
		Unless you planned to run with the JIT compiler disabled (for whatever reason) this is not going to help performance.
		In this second case the compiler is right not to optimize the code.
	forum.java.sun.com /thread.jspa?threadID=558077&tstart=135 (1206 words)

	Embedded.com - Advanced Compiler Optimization Techniques
		Compilers employing the latest optimization technology routinely produce code 20-30% faster than standard compilers, and in some cases, two to three times faster.
		Compilers, of course, do not have to worry about "code reviews" or program maintenance and have no qualms about using constructs such as unstructured jumps ("goto").
		Thus, peephole optimization is still useful to fix inefficiencies for a few corner cases.
	www.embedded.com /showArticle.jhtml?articleID=192200575 (4068 words)

	CMUCL User's Manual: Advanced Compiler Use and Efficiency Hints
		The optimizations described here can have the effect of speeding up existing programs written in conventional styles, but the potential for new programming styles that are clearer and less error-prone is at least as significant.
		Because local call avoids unnecessary call overheads, the compiler internally uses local call to implement some macros and special forms that are not normally thought of as involving a function call.
		Inline expansion is a compiler optimization technique that reduces the overhead of a function call by simply not doing the call: instead, the compiler effectively rewrites the program to appear as though the definition of the called function was inserted at each call site.
	common-lisp.net /project/cmucl/doc/cmu-user/compiler-hint.html (11621 words)

	Crescent Bay Software -- OEM Compiler Technology
		While we do offer some end-user products, our primary business is providing versions of our VAST high-level optimization product (parallelizing, vectorizing, and/or optimizing compiler components) to developers of compiler systems targeting high-speed architectures, whether embedded processors, reconfigurable systems, desktop boxes or supercomputers.
		VAST operates on compiler intermediate representations of the program (such as Edison Design Group IR) or directly on source code (through a compiler driver) to perform high-level optimizations, including loop nest optimizations and automatic vectorization and parallelization.
		It can also pass this information on to the rest of the compiler in a variety of ways, ranging from indicating loops that have no array or pointer dependencies to explicitly adding data dependence arcs for all dependencies in a loop nest.
	www.crescentbaysoftware.com /compilertech.html (399 words)

	Compiler Optimization Settings :: Introducing Real-Time Workshop (Real-Time Workshop) (Site not responding. Last check: )
		In some very rare instances, due to compiler defects, compiler optimizations applied to Real-Time Workshop generated code may cause the executable program to produce incorrect results, even though the code itself is correct.
		Real-Time Workshop uses the default optimization level for each supported compiler.
		You can usually work around problems caused by compiler optimizations by lowering the optimization level of the compiler, or turning off optimizations.
	www.mathworks.com /access/helpdesk_r13/help/toolbox/rtw/rtw_ug/rtw_gs_9.html (134 words)

	Acovea Overview
		This article describes the application of Acovea to the analysis of the GNU C compiler optimization flags; details about the underlying genetic algorithm can be found in the companion article, A Description of the Evolutionary Algorithm.
		An optimization algorithm may be as simple as removing a loop invariant, or as complex as examining an entire program to eliminate global common sub-expressions.
		Optimization is not simple or obvious, and combinations of algorithms can lead to unexpected results.
	www.coyotegulch.com /products/acovea (2420 words)

	Java Compilers
		This list of optimizations that currently have to be done by hand should get shorter as Java compilers improve.
		For each optimization I give before-and-after Java code fragments, and the relevant bytecode (typically an inner loop) that they compile to.
		Adding extra reference variables to allow the compiler to eliminate opcodes or use faster bytecodes can also be considered a case of strength reduction.
	www-2.cs.cmu.edu /~jch/java/compilers.html (558 words)

	Web Pages Related to Compiling Java into Native Code
		It is probably the only way to debug an aggressively optimizing compiler because the debugging process may take (and usually takes) a great deal of time time and it would be simpler to yield to temptation of turning optimization off.
		The whole idea of compiling Java to native code is heresy for Sun Microsystems and they certainly have not done much in the language definition or environment to help the Java to native compiler writer.
		A good optimizing compiler should be able to produce code that is half the size and twice the speed of unoptimized code.
	www.bearcave.com /software/java/comp_java.html (5404 words)

	Application optimization with compilers for Linux on POWER (Site not responding. Last check: )
		Modern compilers often produce optimized code as good as or better than developers can code by hand, and this is accentuated in code written for portability.
		Also, the compiler makes certain assumptions about some of the statements in the code that can potentially be optimized by rewriting that section of the code.
		The GNU Compiler Collection is available for applications already tailored to the GNU extensions or applications that require a common compiler with other build platforms, while the IBM XL C/C++ compiler offers an alternative that can reap high performance rewards for your code.
	www-128.ibm.com /developerworks/library/l-pow-appopt.html?ca=dgr-lnxw07pa-CompilerForPower (4607 words)

	Compiler Optimization (Site not responding. Last check: )
		A scientific calculator is not a highly intensive program on today's systems, but for the more processor intensive program, optimizing the program can be useful to help squeeze a little more performance out of it.
		To set the compiler optimization settings on a project, click on the Target tab (it runs vertically along with the Breakpoints, Bookmarks, Classes, and Files tabs).
		A higher optimization will make debugging more difficult, which can be a pain with more complicated programs.
	www.edenwaith.com /products/edenmath/tutorial/compiler.html (168 words)

	Compiler - Optimizing Compilers for Embedded Systems - Green Hills Software
		Green Hills Optimizing compilers consist of a Language-Specific Front-End, a Global Optimizer, and a Target-Specific Optimizer and Code Generator.
		All Green Hills Optimizing compilers use the same Global Optimizer regardless of language or target, and the same Target-Specific Optimizers and Code Generators regardless of language.
		Optimizations may be optionally weighted for either code speed or minimum size.
	www.ghs.com /products/compiler.html (202 words)

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