diff options
Diffstat (limited to 'share/doc/gccint/Converting-poly_005fints.html')
| -rw-r--r-- | share/doc/gccint/Converting-poly_005fints.html | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/share/doc/gccint/Converting-poly_005fints.html b/share/doc/gccint/Converting-poly_005fints.html new file mode 100644 index 0000000..52755ad --- /dev/null +++ b/share/doc/gccint/Converting-poly_005fints.html @@ -0,0 +1,189 @@ +<!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: Converting poly_ints</title> + +<meta name="description" content="GNU Compiler Collection (GCC) Internals: Converting poly_ints"> +<meta name="keywords" content="GNU Compiler Collection (GCC) Internals: Converting 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="poly_005fint.html#poly_005fint" rel="up" title="poly_int"> +<link href="Miscellaneous-poly_005fint-routines.html#Miscellaneous-poly_005fint-routines" rel="next" title="Miscellaneous poly_int routines"> +<link href="Computing-bounds-on-poly_005fints.html#Computing-bounds-on-poly_005fints" rel="previous" title="Computing bounds on poly_ints"> +<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="Converting-poly_005fints"></a> +<div class="header"> +<p> +Next: <a href="Miscellaneous-poly_005fint-routines.html#Miscellaneous-poly_005fint-routines" accesskey="n" rel="next">Miscellaneous <code>poly_int</code> routines</a>, Previous: <a href="Computing-bounds-on-poly_005fints.html#Computing-bounds-on-poly_005fints" accesskey="p" rel="previous">Computing bounds on <code>poly_int</code>s</a>, Up: <a href="poly_005fint.html#poly_005fint" accesskey="u" rel="up">poly_int</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="Converting-poly_005fints-1"></a> +<h3 class="section">10.7 Converting <code>poly_int</code>s</h3> + +<p>A <code>poly_int<<var>n</var>, <var>T</var>></code> can be constructed from up to +<var>n</var> individual <var>T</var> coefficients, with the remaining coefficients +being implicitly zero. In particular, this means that every +<code>poly_int<<var>n</var>, <var>T</var>></code> can be constructed from a single +scalar <var>T</var>, or something compatible with <var>T</var>. +</p> +<p>Also, a <code>poly_int<<var>n</var>, <var>T</var>></code> can be constructed from +a <code>poly_int<<var>n</var>, <var>U</var>></code> if <var>T</var> can be constructed +from <var>U</var>. +</p> +<p>The following functions provide other forms of conversion, +or test whether such a conversion would succeed. +</p> +<dl compact="compact"> +<dt>‘<samp><var>value</var>.is_constant ()</samp>’</dt> +<dd><p>Return true if <code>poly_int</code> <var>value</var> is a compile-time constant. +</p> +</dd> +<dt>‘<samp><var>value</var>.is_constant (&<var>c1</var>)</samp>’</dt> +<dd><p>Return true if <code>poly_int</code> <var>value</var> is a compile-time constant, +storing it in <var>c1</var> if so. <var>c1</var> must be able to hold all +constant values of <var>value</var> without loss of precision. +</p> +</dd> +<dt>‘<samp><var>value</var>.to_constant ()</samp>’</dt> +<dd><p>Assert that <var>value</var> is a compile-time constant and return its value. +When using this function, please add a comment explaining why the +condition is known to hold (for example, because an earlier phase +of analysis rejected non-constants). +</p> +</dd> +<dt>‘<samp><var>value</var>.to_shwi (&<var>p2</var>)</samp>’</dt> +<dd><p>Return true if ‘<samp>poly_int<<var>N</var>, <var>T</var>></samp>’ <var>value</var> can be +represented without loss of precision as a +‘<samp>poly_int<<var>N</var>, <code>HOST_WIDE_INT</code>></samp>’, storing it in that +form in <var>p2</var> if so. +</p> +</dd> +<dt>‘<samp><var>value</var>.to_uhwi (&<var>p2</var>)</samp>’</dt> +<dd><p>Return true if ‘<samp>poly_int<<var>N</var>, <var>T</var>></samp>’ <var>value</var> can be +represented without loss of precision as a +‘<samp>poly_int<<var>N</var>, <code>unsigned HOST_WIDE_INT</code>></samp>’, storing it in that +form in <var>p2</var> if so. +</p> +</dd> +<dt>‘<samp><var>value</var>.force_shwi ()</samp>’</dt> +<dd><p>Forcibly convert each coefficient of ‘<samp>poly_int<<var>N</var>, <var>T</var>></samp>’ +<var>value</var> to <code>HOST_WIDE_INT</code>, truncating any that are out of range. +Return the result as a ‘<samp>poly_int<<var>N</var>, <code>HOST_WIDE_INT</code>></samp>’. +</p> +</dd> +<dt>‘<samp><var>value</var>.force_uhwi ()</samp>’</dt> +<dd><p>Forcibly convert each coefficient of ‘<samp>poly_int<<var>N</var>, <var>T</var>></samp>’ +<var>value</var> to <code>unsigned HOST_WIDE_INT</code>, truncating any that are +out of range. Return the result as a +‘<samp>poly_int<<var>N</var>, <code>unsigned HOST_WIDE_INT</code>></samp>’. +</p> +</dd> +<dt>‘<samp>wi::shwi (<var>value</var>, <var>precision</var>)</samp>’</dt> +<dd><p>Return a <code>poly_int</code> with the same value as <var>value</var>, but with +the coefficients converted from <code>HOST_WIDE_INT</code> to <code>wide_int</code>. +<var>precision</var> specifies the precision of the <code>wide_int</code> cofficients; +if this is wider than a <code>HOST_WIDE_INT</code>, the coefficients of +<var>value</var> will be sign-extended to fit. +</p> +</dd> +<dt>‘<samp>wi::uhwi (<var>value</var>, <var>precision</var>)</samp>’</dt> +<dd><p>Like <code>wi::shwi</code>, except that <var>value</var> has coefficients of +type <code>unsigned HOST_WIDE_INT</code>. If <var>precision</var> is wider than +a <code>HOST_WIDE_INT</code>, the coefficients of <var>value</var> will be +zero-extended to fit. +</p> +</dd> +<dt>‘<samp>wi::sext (<var>value</var>, <var>precision</var>)</samp>’</dt> +<dd><p>Return a <code>poly_int</code> of the same type as <var>value</var>, sign-extending +every coefficient from the low <var>precision</var> bits. This in effect +applies <code>wi::sext</code> to each coefficient individually. +</p> +</dd> +<dt>‘<samp>wi::zext (<var>value</var>, <var>precision</var>)</samp>’</dt> +<dd><p>Like <code>wi::sext</code>, but for zero extension. +</p> +</dd> +<dt>‘<samp>poly_wide_int::from (<var>value</var>, <var>precision</var>, <var>sign</var>)</samp>’</dt> +<dd><p>Convert <var>value</var> to a <code>poly_wide_int</code> in which each coefficient +has <var>precision</var> bits. Extend the coefficients according to +<var>sign</var> if the coefficients have fewer bits. +</p> +</dd> +<dt>‘<samp>poly_offset_int::from (<var>value</var>, <var>sign</var>)</samp>’</dt> +<dd><p>Convert <var>value</var> to a <code>poly_offset_int</code>, extending its coefficients +according to <var>sign</var> if they have fewer bits than <code>offset_int</code>. +</p> +</dd> +<dt>‘<samp>poly_widest_int::from (<var>value</var>, <var>sign</var>)</samp>’</dt> +<dd><p>Convert <var>value</var> to a <code>poly_widest_int</code>, extending its coefficients +according to <var>sign</var> if they have fewer bits than <code>widest_int</code>. +</p></dd> +</dl> + +<hr> +<div class="header"> +<p> +Next: <a href="Miscellaneous-poly_005fint-routines.html#Miscellaneous-poly_005fint-routines" accesskey="n" rel="next">Miscellaneous <code>poly_int</code> routines</a>, Previous: <a href="Computing-bounds-on-poly_005fints.html#Computing-bounds-on-poly_005fints" accesskey="p" rel="previous">Computing bounds on <code>poly_int</code>s</a>, Up: <a href="poly_005fint.html#poly_005fint" accesskey="u" rel="up">poly_int</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> + + + +</body> +</html> |