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91 lines
4.2 KiB
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<title>Tree SSA - GNU Compiler Collection (GCC) Internals</title>
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<link rel="prev" href="GIMPLE.html#GIMPLE" title="GIMPLE">
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A GNU Manual
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<a name="Tree-SSA"></a>
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<p>
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Next: <a rel="next" accesskey="n" href="RTL.html#RTL">RTL</a>,
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Previous: <a rel="previous" accesskey="p" href="GIMPLE.html#GIMPLE">GIMPLE</a>,
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Up: <a rel="up" accesskey="u" href="index.html#Top">Top</a>
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<h2 class="chapter">12 Analysis and Optimization of GIMPLE tuples</h2>
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<p><a name="index-Tree-SSA-2505"></a><a name="index-Optimization-infrastructure-for-GIMPLE-2506"></a>
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GCC uses three main intermediate languages to represent the program
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during compilation: GENERIC, GIMPLE and RTL. GENERIC is a
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language-independent representation generated by each front end. It
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is used to serve as an interface between the parser and optimizer.
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GENERIC is a common representation that is able to represent programs
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written in all the languages supported by GCC.
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<p>GIMPLE and RTL are used to optimize the program. GIMPLE is used for
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target and language independent optimizations (e.g., inlining,
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constant propagation, tail call elimination, redundancy elimination,
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etc). Much like GENERIC, GIMPLE is a language independent, tree based
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representation. However, it differs from GENERIC in that the GIMPLE
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grammar is more restrictive: expressions contain no more than 3
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operands (except function calls), it has no control flow structures
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and expressions with side-effects are only allowed on the right hand
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side of assignments. See the chapter describing GENERIC and GIMPLE
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for more details.
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<p>This chapter describes the data structures and functions used in the
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GIMPLE optimizers (also known as “tree optimizers” or “middle
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end”). In particular, it focuses on all the macros, data structures,
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functions and programming constructs needed to implement optimization
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passes for GIMPLE.
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<ul class="menu">
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<li><a accesskey="1" href="Annotations.html#Annotations">Annotations</a>: Attributes for variables.
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<li><a accesskey="2" href="SSA-Operands.html#SSA-Operands">SSA Operands</a>: SSA names referenced by GIMPLE statements.
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<li><a accesskey="3" href="SSA.html#SSA">SSA</a>: Static Single Assignment representation.
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<li><a accesskey="4" href="Alias-analysis.html#Alias-analysis">Alias analysis</a>: Representing aliased loads and stores.
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<li><a accesskey="5" href="Memory-model.html#Memory-model">Memory model</a>: Memory model used by the middle-end.
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</ul>
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</body></html>
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