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| author | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
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| committer | alk3pInjection <webmaster@raspii.tech> | 2024-02-04 16:16:35 +0800 |
| commit | abdaadbcae30fe0c9a66c7516798279fdfd97750 (patch) | |
| tree | 00a54a6e25601e43876d03c1a4a12a749d4a914c /share/doc/gccint/RTL-SSA-Instructions.html | |
https://developer.arm.com/downloads/-/arm-gnu-toolchain-downloads
Change-Id: I7303388733328cd98ab9aa3c30236db67f2e9e9c
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diff --git a/share/doc/gccint/RTL-SSA-Instructions.html b/share/doc/gccint/RTL-SSA-Instructions.html new file mode 100644 index 0000000..a0fb1d2 --- /dev/null +++ b/share/doc/gccint/RTL-SSA-Instructions.html @@ -0,0 +1,128 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> +<html> +<!-- Copyright (C) 1988-2023 Free Software Foundation, Inc. + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.3 or +any later version published by the Free Software Foundation; with the +Invariant Sections being "Funding Free Software", the Front-Cover +Texts being (a) (see below), and with the Back-Cover Texts being (b) +(see below). A copy of the license is included in the section entitled +"GNU Free Documentation License". + +(a) The FSF's Front-Cover Text is: + +A GNU Manual + +(b) The FSF's Back-Cover Text is: + +You have freedom to copy and modify this GNU Manual, like GNU + software. Copies published by the Free Software Foundation raise + funds for GNU development. --> +<!-- Created by GNU Texinfo 5.1, http://www.gnu.org/software/texinfo/ --> +<head> +<title>GNU Compiler Collection (GCC) Internals: RTL SSA Instructions</title> + +<meta name="description" content="GNU Compiler Collection (GCC) Internals: RTL SSA Instructions"> +<meta name="keywords" content="GNU Compiler Collection (GCC) Internals: RTL SSA Instructions"> +<meta name="resource-type" content="document"> +<meta name="distribution" content="global"> +<meta name="Generator" content="makeinfo"> +<meta http-equiv="Content-Type" content="text/html; charset=utf-8"> +<link href="index.html#Top" rel="start" title="Top"> +<link href="Option-Index.html#Option-Index" rel="index" title="Option Index"> +<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> +<link href="RTL-SSA.html#RTL-SSA" rel="up" title="RTL SSA"> +<link href="RTL-SSA-Basic-Blocks.html#RTL-SSA-Basic-Blocks" rel="next" title="RTL SSA Basic Blocks"> +<link href="Using-RTL-SSA.html#Using-RTL-SSA" rel="previous" title="Using RTL SSA"> +<style type="text/css"> +<!-- +a.summary-letter {text-decoration: none} +blockquote.smallquotation {font-size: smaller} +div.display {margin-left: 3.2em} +div.example {margin-left: 3.2em} +div.indentedblock {margin-left: 3.2em} +div.lisp {margin-left: 3.2em} +div.smalldisplay {margin-left: 3.2em} +div.smallexample {margin-left: 3.2em} +div.smallindentedblock {margin-left: 3.2em; font-size: smaller} +div.smalllisp {margin-left: 3.2em} +kbd {font-style:oblique} +pre.display {font-family: inherit} +pre.format {font-family: inherit} +pre.menu-comment {font-family: serif} +pre.menu-preformatted {font-family: serif} +pre.smalldisplay {font-family: inherit; font-size: smaller} +pre.smallexample {font-size: smaller} +pre.smallformat {font-family: inherit; font-size: smaller} +pre.smalllisp {font-size: smaller} +span.nocodebreak {white-space:nowrap} +span.nolinebreak {white-space:nowrap} +span.roman {font-family:serif; font-weight:normal} +span.sansserif {font-family:sans-serif; font-weight:normal} +ul.no-bullet {list-style: none} +--> +</style> + + +</head> + +<body lang="en" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#800080" alink="#FF0000"> +<a name="RTL-SSA-Instructions"></a> +<div class="header"> +<p> +Next: <a href="RTL-SSA-Basic-Blocks.html#RTL-SSA-Basic-Blocks" accesskey="n" rel="next">RTL SSA Basic Blocks</a>, Previous: <a href="Using-RTL-SSA.html#Using-RTL-SSA" accesskey="p" rel="previous">Using RTL SSA</a>, Up: <a href="RTL-SSA.html#RTL-SSA" accesskey="u" rel="up">RTL SSA</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p> +</div> +<hr> +<a name="RTL-SSA-Instructions-1"></a> +<h4 class="subsection">14.21.2 RTL SSA Instructions</h4> + +<a name="index-RPO"></a> +<a name="index-reverse-postorder"></a> +<a name="index-instructions_002c-RTL-SSA"></a> +<a name="index-rtl_005fssa_003a_003ainsn_005finfo"></a> +<p>RTL SSA instructions are represented by an <code>rtl_ssa::insn_info</code>. +These instructions are chained together in a single list that follows +a reverse postorder (RPO) traversal of the function. This means that +if any path through the function can execute an instruction <var>I1</var> +and then later execute an instruction <var>I2</var> for the first time, +<var>I1</var> appears before <var>I2</var> in the list<a name="DOCF4" href="#FOOT4"><sup>4</sup></a>. +</p> +<p>Two RTL SSA instructions can be compared to find which instruction +occurs earlier than the other in the RPO. One way to do this is +to use the C++ comparison operators, such as: +</p> +<div class="example"> +<pre class="example">*<var>insn1</var> < *<var>insn2</var> +</pre></div> + +<p>Another way is to use the <code>compare_with</code> function: +</p> +<div class="example"> +<pre class="example"><var>insn1</var>->compare_with (<var>insn2</var>) +</pre></div> + +<p>This expression is greater than zero if <var>insn1</var> comes after <var>insn2</var> +in the RPO, less than zero if <var>insn1</var> comes before <var>insn2</var> in the +RPO, or zero if <var>insn1</var> and <var>insn2</var> are the same. This order is +maintained even if instructions are added to the function or moved around. +</p> +<p>The main purpose of <code>rtl_ssa::insn_info</code> is to hold +SSA information about an instruction. However, it also caches +certain properties of the instruction, such as whether it is an +inline assembly instruction, whether it has volatile accesses, and so on. +</p> +<div class="footnote"> +<hr> +<h4 class="footnotes-heading">Footnotes</h4> + +<h3><a name="FOOT4" href="#DOCF4">(4)</a></h3> +<p>Note that this +order is different from the order of the underlying RTL instructions, +which follow machine code order instead.</p> +</div> + + + +</body> +</html> |