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Topic: Sparse conditional constant propagation


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In the News (Fri 17 Feb 12)

  
  Discriminative Models for 3D Human Motion Reconstruction
In practice, we do estimation using conditionals represented as Bayesian mixtures (see next section) and the temporal prior, also propagates as a Gaussian mixture, each having, say M components.
The means of this expanded posterior are clustered and the centers are used to initialize a reduced M-component approximation that is refined using variational optimization.
The first two rows show models that are based on random regression and joint density (the conditional is obtained from the joint distribution, by applying Bayes' rule, conditioning and marginalization).
www.cs.toronto.edu /~crismin/discriminative_human_tracking.html   (1484 words)

  
  Optimization Passes for Machine Suif   (Site not responding. Last check: 2007-10-28)
The goal of constant propagation is to discover values that are constants on all possible executions of a program and to propagate these constants values as far through the program as possible.
Sparse Conditional Constant Propagation (SCCP) is an algorithm developed by Wegman and Zadeck.
This variant of constant propagation is a powerful algorithm for determining constants in a single procedure.
lapwww.epfl.ch /dev/machsuif/opt_passes/index.php   (506 words)

  
  compiler optimization   (Site not responding. Last check: 2007-10-28)
sparse conditional constant propagation : Effectively equivalent to iteratively performing constant propagation, constant folding, and dead code elimination until there is no change, but is much more efficient.
This optimization symbolically executes the program, simultaneously propagating constant values and eliminating portions of the control flow graph that this makes unreachable.
the assignment of a constant into a variable) appear inside a loop, they can be moved out of it because their effect will be the same no matter if they're executed many times or just once.
www.yourencyclopedia.net /compiler_optimization.html   (3339 words)

  
 Compiler Optimization Encyclopedia Article, History, Biography @ Local Color Art   (Site not responding. Last check: 2007-10-28)
Doing so duplicates the condition check (increasing the size of the code) but is more efficient because jumps usually cause a pipeline stall.
Unswitching moves a conditional inside a loop outside of it by duplicating the loop's body, and placing a version of it inside each of the if and else clauses of the conditional.
In this pass, conditional jumps in the code that branch to identical or inverse tests are detected, and can be "threaded" through a second conditional test.
www.stardustmemories.com /search/encyclopedia/Compiler_optimization   (3691 words)

  
 Encyclopedia: GNU Compiler Collection   (Site not responding. Last check: 2007-10-28)
GCC developers have given this part of the compiler the somewhat contradictory name the "middle end." These optimizations include dead code elimination, partial redundancy elimination, global value numbering, sparse conditional constant propagation, and scalar replacement of aggregates.
Sparse conditional constant propagation is an optimization frequently utilized in compilers after conversion to static single assignment form (SSA).
The behavior of the GCC back end is partly specified by preprocessor macros and functions specific to a target architecture, for instance to define the endianness, word size, and calling conventions.
www.nationmaster.com /encyclopedia/GNU-Compiler-Collection   (3663 words)

  
 Compiler optimization   (Site not responding. Last check: 2007-10-28)
Unswitching moves a conditional inside a loop outside of it by duplicating the loop's body, and placing a version of itinside each of the if and else clauses of the conditional.
sparse conditional constant propagation : Effectively equivalent to iterativelyperforming constant propagation, constant folding, and dead code elimination until there is no change, but is much more efficient.
This optimizationsymbolically executes the program, simultaneously propagating constant values and eliminating portions of the control flow graph that this makes unreachable.
www.therfcc.org /compiler-optimization-38461.html   (3031 words)

  
 Optimization Passes for Machine Suif
Expressions whose operands are all constants can be evaluated at compile time and the result propagated further.
Sparse Conditional Constant Propagation (SCCP) is an algorithm developed by Wegman and Zadeck.
It can discovers all constants that can be found by evaluating all conditional branches with all constant operands.
lap.epfl.ch /dev/machsuif/opt_passes/index.php   (506 words)

  
 Rich Sutton's Publications
Sanger, T.D., Sutton, R.S., Matheus, C.J. Iterative construction of sparse polynomial approximations.
This aspect of classical conditioning has been largely neglected by hypotheses that neurons provide single unit analogs of classical conditioning.
We suggest that an essential feature of classical conditioning that has been largely overlooked by adaptive network theorists is its predictive nature.
web.cs.ualberta.ca /~sutton/publications.html   (12471 words)

  
 Compiler optimization   (Site not responding. Last check: 2007-10-28)
; sparse conditional constant propagation : Effectively equivalent to iteratively performing constant propagation, constant folding, and dead code elimination until there is no change, but is much more efficient.
Bounds-checking elimination allows the compiler to safely remove bounds-checking in many situations where it can determine that the index must fall within valid bounds, for example if it is a simple loop variable.
Several peephole optimization s also fall into this category, such as replacing division by a constant with multiplication by its reciprocal, converting multiplies into a series of bit-shifts and adds, and replacing large instructions with equivalent smaller ones that load more quickly.
www.serebella.com /encyclopedia/article-Compiler_optimization.html   (3627 words)

  
 The Devilfinder Search Engine - Constant propagation with conditional branches - Finding Stuff Since 1979.
Citations: Constant propagation with conditional branches - Wegman...
Constant propagation can also cause conditional branches to simplify to one or more unconditional statements, when the conditional expression can be...
Sparse conditional constant propagation is an optimization frequently utilized in...
www.devilfinder.com /find.php?q=Constant+propagation+with+conditional+branches   (4147 words)

  
 [No title]   (Site not responding. Last check: 2007-10-28)
Andrew Begel CS302 PS4 Case Studies Constant propagation is an important phase of optimization.
This assignment asks you to design and implement a constant propagation algorithm for an imaginary intermediate representation for a Java-like imperative language.
First, determining when it would be ok to replace a variable reference by a propagated constant, and second, actually enacting the transformation.
www.cs.berkeley.edu /~abegel/cs302/ps4.txt   (1112 words)

  
 Sparse Conditional Constant Propagation - GNU Project - Free Software Foundation (FSF)   (Site not responding. Last check: 2007-10-28)
Daniel Berlin and Jeff Law have contributed an SSA based sparse conditional constant optimization (SSA CCP) pass to GCC.
SSA CPP is an aggressive constant propagation algorithm that performs traditional global constant propagation, but also uses the SSA graph to identify and optimize away branches which it can prove can never be taken.
in the true arm of the first conditional will normally create a runtime branch to assign the value 1 or 0 to neg depending on neg's previous value.
www.gnu.org /software/gcc/news/ssa-ccp.html   (419 words)

  
 [No title]
3 clean 3 constant 3 expand 3 becomes 3 rationale 3 reduces 3 package 3 nearly 3 precisely 3 estimate 3 belief 3 reed 3 seen 3 simultaneous 3 angeles 3 transformations.
1 age 1 coordinate 1 christensen 1 graphs: 1 stepwise 1 minkowski 1 lies 1 propagates 1 coda 1 hancock 1 caltech 1 distributivity 1 23:00 1 noudehou 1 mal 1 dmm@cs.cmu.edu 1 seidenfeld 1 agent.
1 18:58 1 concept: 1 branches 1 sunday 1 constants 1 vienna 1 attributive 1 hungry 1 extensionality 1 sum.
simson.net /ref/2003/6.863J/report/wordscount.txt   (17824 words)

  
 LLVM: SCCP.cpp Source File   (Site not responding. Last check: 2007-10-28)
00001 //===- SCCP.cpp - Sparse Conditional Constant Propagation -----------------===// 00002 // 00003 // The LLVM Compiler Infrastructure 00004 // 00005 // This file was developed by the LLVM research group and is distributed under 00006 // the University of Illinois Open Source License.
If a conditional branch has a value that is constant, make the selected 00473 // destination executable 00474 // 7.
If they are all 00506 // constant, and they agree with each other, the PHI becomes the identical 00507 // constant.
illuvium.com /docs/doxygen/SCCP_8cpp-source.html   (5490 words)

  
 Citations: ACM Transactions on Programming Languages and Systems - Click, Cooper, combining (ResearchIndex)
The necessary analysis has much in common with the Wegman and Zadeck s Sparse Conditional Constant optimization [16] where the constants being propagated can be imagined as constant pointers to class instances.
For example, each of Wegman and Zadeck s conditional constant propagation algorithms [28, 29] is a specialpurpose monolithic super analysis that simultaneously performs constant propagation and unreachable code elimination.
He shows that with constant propagation, global value numbering, and dead code elimination, doing a combined analyses leads to more optimization opportunities.
citeseer.ist.psu.edu /context/488735/0   (2614 words)

  
 AMD GCC SPEC CPU Flags
This include use of conditional moves, min, max, set flags and abs instructions, and some tricks doable by standard arithmetics.
The use of conditional execution on chips where it is available is controlled by if-conversion2.
This is similar to the constant propagation pass, but instead of values, ranges of values are propagated.
www.spec.org /cpu2006/flags/CPU2006_flags.xml   (2950 words)

  
 [No title]   (Site not responding. Last check: 2007-10-28)
I'd also add an audiotape piece to the case study, where students must explain their reasoning to the "person behind the tape" who must gain enough knowledge to understand and implement constant propagation on their own.
I think this explanatory phase (as based on Elizabeth Cohen's paper) of work would be able to prevent students from skipping over questions they don't feel like answering, as well as making it easier for an evaluator to gauge how much the students know.
Implement the sparse conditional constant propagation in Java, given SSA form data structures, graph traversal algorithms.
www.cs.berkeley.edu /~abegel/cs302/ps7.txt   (857 words)

  
 NIPS : Web : Groups : NIPS2000 : NIPS*2000 Online Abstracts and Papers   (Site not responding. Last check: 2007-10-28)
Modeling high-dimensional discrete random variables without significant a priori knowledge of conditional independence is intrinsically difficult because of the curse of dimensionality: combinations of values on which the model will be tested are likely to be different from all the combinations of values seen in the training data.
We present a simple sparse greedy technique to approximate the maximum a posteriori estimate of Gaussian Processes with much improved scaling behaviour in the sample size $m$.
Unfortunately, the technique is not `sparse', since the components thus obtained are expressed in terms of kernels associated with every training vector.
www.nips.cc /Web/Groups/NIPS/NIPS2000/00abstracts.html   (17926 words)

  
 Graphical Models
The simplest conditional independence relationship encoded in a Bayesian network can be stated as follows: a node is independent of its ancestors given its parents, where the ancestor/parent relationship is with respect to some fixed topological ordering of the nodes.
Finally, consider the case in which we have one incoming and outgoing arrow to X. It is intuitive that the nodes upstream and downstream of X are dependent iff X is hidden, because conditioning on a node breaks the graph at that point.
Belief propagation is equivalent to exact inference on a modified graph, called the universal cover or unwrapped/ computation tree, which has the same local topology as the original graph.
www.cs.ubc.ca /~murphyk/Bayes/bayes.html   (6479 words)

  
 [No title]   (Site not responding. Last check: 2007-10-28)
The -ipsccp pass should be a very powerful CCP implementation, based off of the standard SCCP formulation, but extended to work interprocedurally.
In particular, the algorithm should be able to handle CCP load instructions from internal globals that are and are not marked as constant.
In particular, the following global should be marked constant: void test() { static int i = 0; if (i) --i; // dead store } This will come up a lot when we start doing optimization of the %llvm.global_ctors list.
www.nondot.org /~sabre/LLVMNotes/IP-SCCP.txt   (192 words)

  
 Compiler optimization   (Site not responding. Last check: 2007-10-28)
loop unrolling : Duplicates the body of the loop multiple times, in order to decrease the number of times the loop condition is tested and the number of jumps, which hurt performance by impairing the instruction pipeline.
loop unswitching : Unswitching moves a conditional inside a loop outside of it by duplicating the loop's body, and placing a version of it inside each of the if and else clauses of the conditional.
constant folding and propagation : replacing expressions consisting of constants (e.g.
www.worldhistory.com /wiki/C/Compiler-optimization.htm   (3462 words)

  
 Conditional Constant Propagation   (Site not responding. Last check: 2007-10-28)
Wegman and Zadeck's Sparse Conditional Constant (SCC) algorithm was used to find constant expressions, constant conditions, and unreachable code [
In addition, every flow-graph node (corresponding to a quadruple) is marked as executable or non-executable.
We then walk the flow-graph, eliminating dead-code (quadruples marked non-executable), replacing constant variables with their values, and changing constant conditional branches to
www.cscott.net /Projects/ele580a/node10.html   (99 words)

  
 sparse - OneLook Dictionary Search
Tip: Click on the first link on a line below to go directly to a page where "sparse" is defined.
Phrases that include sparse: sparse matrix, pim sparse, sparse binary polynomial hashing, sparse coding, sparse conditional constant propagation, more...
Words similar to sparse: thin, sparsely, sparseness, sparser, sparsest, sparsity, meager, scant, scanty, more...
www.onelook.com /?ls=a&w=sparse   (218 words)

  
 gcc - phpMan
Writing into string constants is a very bad idea; "constants" should be constant.
This option is intended to warn when the compiler detects that at least a whole line of source code will never be executed, because some condition is never satisfied or because it is after a procedure that never returns.
It is possible for this option to produce a warning even though there are circumstances under which part of the affected line can be executed, so care should be taken when removing apparently-unreachable code.
phpunixman.sourceforge.net /index.php/info/gcc   (16545 words)

  
 Computer Programming Software Terms, Glossary and Dictionary - S
A software license is an agreemt with certain terms and conditions that grant permission to do things with computer software that would otherwise be prohibited by copyright law.
If one does not follow the terms of the license, then he or she is subject to the normal restrictions of copyright law.
Sparse conditional constant propagation is an optimization frequently utilized in compilers after conversion to static single assignment form (SSA).
www.networkdictionary.com /software/s.php   (8821 words)

  
 LLVM 1.0 Release Notes
Conditionals : Omitting the middle operand of a
It is possible that it will have to be adjusted to support other C compilers.
C backend fails on constant cast expr to ptr-to-anonymous struct
llvm.cs.uiuc.edu /releases/1.0/docs/ReleaseNotes.html   (1609 words)

  
 GCC news and announcements - GNU Project - Free Software Foundation (FSF)
A forward propagation pass on RTL was contributed by Paolo Bonzini of University of Lugano, and Steven Bosscher while working for Novell.
Daniel Berlin and Jeff Law have contributed a Sparse Conditional Constant Propagation optimization pass.
In addition, it also has support for conditional (predicated) execution, such as is found in the Intel IA-64 architecture, the ARM processors, and numerous embedded LIW and DSP parts.
gcc.gnu.org /news.html   (3819 words)

  
 SSA for Trees - GNU Project - Free Software Foundation (FSF)
Dominator-based optimizations such as copy propagation, constant propagation and redundancy elimination using value numbering [3].
It assigns symbolic values to expressions such that if two expression have the same symbolic value, they compute the same value.
This optimization tracks the weighted value ranges of variables through a program, much like constant propagation.
gcc.gnu.org /projects/tree-ssa   (1717 words)

  
 gcc(1)
Options Controlling C++ Dialect This section describes the command-line options that are only meaningful for C++ programs; but you can also use most of the GNU compiler options regardless of what language your program is in.
W Dump after SSA conditional constant propagation, to file.
When used in conjunction with -fgcse-lm, loops containing a load/store sequence can be changed to a load before the loop and a store after the loop.
www.astro.caltech.edu /cgi-bin/man.cgi?section=1&topic=gcc   (14716 words)

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