visus
/
toolchain-gcc-arm-embedded


			
							<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<!-- Copyright (C) 1988-2020 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 6.5, http://www.gnu.org/software/texinfo/ -->
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Computing bounds on poly_ints (GNU Compiler Collection (GCC) Internals)</title>

<meta name="description" content="Computing bounds on poly_ints (GNU Compiler Collection (GCC) Internals)">
<meta name="keywords" content="Computing bounds on poly_ints (GNU Compiler Collection (GCC) Internals)">
<meta name="resource-type" content="document">
<meta name="distribution" content="global">
<meta name="Generator" content="makeinfo">
<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="poly_005fint.html#poly_005fint" rel="up" title="poly_int">
<link href="Converting-poly_005fints.html#Converting-poly_005fints" rel="next" title="Converting poly_ints">
<link href="Alignment-of-poly_005fints.html#Alignment-of-poly_005fints" rel="prev" title="Alignment of poly_ints">
<style type="text/css">
<!--
a.summary-letter {text-decoration: none}
blockquote.indentedblock {margin-right: 0em}
blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
blockquote.smallquotation {font-size: smaller}
div.display {margin-left: 3.2em}
div.example {margin-left: 3.2em}
div.lisp {margin-left: 3.2em}
div.smalldisplay {margin-left: 3.2em}
div.smallexample {margin-left: 3.2em}
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.nolinebreak {white-space: nowrap}
span.roman {font-family: initial; font-weight: normal}
span.sansserif {font-family: sans-serif; font-weight: normal}
ul.no-bullet {list-style: none}
-->
</style>


</head>

<body lang="en">
<a name="Computing-bounds-on-poly_005fints"></a>
<div class="header">
<p>
Next: <a href="Converting-poly_005fints.html#Converting-poly_005fints" accesskey="n" rel="next">Converting <code>poly_int</code>s</a>, Previous: <a href="Alignment-of-poly_005fints.html#Alignment-of-poly_005fints" accesskey="p" rel="prev">Alignment of <code>poly_int</code>s</a>, Up: <a href="poly_005fint.html#poly_005fint" accesskey="u" rel="up">poly_int</a> &nbsp; [<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="Computing-bounds-on-poly_005fints-1"></a>
<h3 class="section">10.6 Computing bounds on <code>poly_int</code>s</h3>

<p><code>poly_int</code> also provides routines for calculating lower and upper bounds:
</p>
<dl compact="compact">
<dt>&lsquo;<samp>constant_lower_bound (<var>a</var>)</samp>&rsquo;</dt>
<dd><p>Assert that <var>a</var> is nonnegative and return the smallest value it can have.
</p>
</dd>
<dt>&lsquo;<samp>constant_lower_bound_with_limit (<var>a</var>, <var>b</var>)</samp>&rsquo;</dt>
<dd><p>Return the least value <var>a</var> can have, given that the context in
which <var>a</var> appears guarantees that the answer is no less than <var>b</var>.
In other words, the caller is asserting that <var>a</var> is greater than or
equal to <var>b</var> even if &lsquo;<samp>known_ge (<var>a</var>, <var>b</var>)</samp>&rsquo; doesn&rsquo;t hold.
</p>
</dd>
<dt>&lsquo;<samp>constant_upper_bound_with_limit (<var>a</var>, <var>b</var>)</samp>&rsquo;</dt>
<dd><p>Return the greatest value <var>a</var> can have, given that the context in
which <var>a</var> appears guarantees that the answer is no greater than <var>b</var>.
In other words, the caller is asserting that <var>a</var> is less than or equal
to <var>b</var> even if &lsquo;<samp>known_le (<var>a</var>, <var>b</var>)</samp>&rsquo; doesn&rsquo;t hold.
</p>
</dd>
<dt>&lsquo;<samp>lower_bound (<var>a</var>, <var>b</var>)</samp>&rsquo;</dt>
<dd><p>Return a value that is always less than or equal to both <var>a</var> and <var>b</var>.
It will be the greatest such value for some indeterminate values
but necessarily for all.
</p>
</dd>
<dt>&lsquo;<samp>upper_bound (<var>a</var>, <var>b</var>)</samp>&rsquo;</dt>
<dd><p>Return a value that is always greater than or equal to both <var>a</var> and
<var>b</var>.  It will be the least such value for some indeterminate values
but necessarily for all.
</p></dd>
</dl>


</body>
</html>