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diff --git a/share/doc/gccint/Comparing-potentially_002dunordered-poly_005fints.html b/share/doc/gccint/Comparing-potentially_002dunordered-poly_005fints.html new file mode 100644 index 0000000..51cf343 --- /dev/null +++ b/share/doc/gccint/Comparing-potentially_002dunordered-poly_005fints.html @@ -0,0 +1,105 @@ +<!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). 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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: Comparing potentially-unordered poly_ints</title> + +<meta name="description" content="GNU Compiler Collection (GCC) Internals: Comparing potentially-unordered poly_ints"> +<meta name="keywords" content="GNU Compiler Collection (GCC) Internals: Comparing potentially-unordered poly_ints"> +<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="Comparisons-involving-poly_005fint.html#Comparisons-involving-poly_005fint" rel="up" title="Comparisons involving poly_int"> +<link href="Comparing-ordered-poly_005fints.html#Comparing-ordered-poly_005fints" rel="next" title="Comparing ordered poly_ints"> +<link href="Properties-of-the-poly_005fint-comparisons.html#Properties-of-the-poly_005fint-comparisons" rel="previous" title="Properties of the poly_int comparisons"> +<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="Comparing-potentially_002dunordered-poly_005fints"></a> +<div class="header"> +<p> +Next: <a href="Comparing-ordered-poly_005fints.html#Comparing-ordered-poly_005fints" accesskey="n" rel="next">Comparing ordered <code>poly_int</code>s</a>, Previous: <a href="Properties-of-the-poly_005fint-comparisons.html#Properties-of-the-poly_005fint-comparisons" accesskey="p" rel="previous">Properties of the <code>poly_int</code> comparisons</a>, Up: <a href="Comparisons-involving-poly_005fint.html#Comparisons-involving-poly_005fint" accesskey="u" rel="up">Comparisons involving <code>poly_int</code></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="Comparing-potentially_002dunordered-poly_005fints-1"></a> +<h4 class="subsection">10.3.3 Comparing potentially-unordered <code>poly_int</code>s</h4> + +<p>In cases where there is no definite link between two <code>poly_int</code>s, +we can usually make a conservatively-correct assumption. For example, +the conservative assumption for alias analysis is that two references +<em>might</em> alias. +</p> +<p>One way of checking whether [<var>begin1</var>, <var>end1</var>) might overlap +[<var>begin2</var>, <var>end2</var>) using the <code>poly_int</code> comparisons is: +</p> +<div class="smallexample"> +<pre class="smallexample">maybe_gt (<var>end1</var>, <var>begin2</var>) && maybe_gt (<var>end2</var>, <var>begin1</var>) +</pre></div> + +<p>and another (equivalent) way is: +</p> +<div class="smallexample"> +<pre class="smallexample">!(known_le (<var>end1</var>, <var>begin2</var>) || known_le (<var>end2</var>, <var>begin1</var>)) +</pre></div> + +<p>However, in this particular example, it is better to use the range helper +functions instead. See <a href="Range-checks-on-poly_005fints.html#Range-checks-on-poly_005fints">Range checks on <code>poly_int</code>s</a>. +</p> + + + +</body> +</html> |