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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/Machine_002dIndependent-Predicates.html | |
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diff --git a/share/doc/gccint/Machine_002dIndependent-Predicates.html b/share/doc/gccint/Machine_002dIndependent-Predicates.html new file mode 100644 index 0000000..92c4929 --- /dev/null +++ b/share/doc/gccint/Machine_002dIndependent-Predicates.html @@ -0,0 +1,242 @@ +<!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: Machine-Independent Predicates</title> + +<meta name="description" content="GNU Compiler Collection (GCC) Internals: Machine-Independent Predicates"> +<meta name="keywords" content="GNU Compiler Collection (GCC) Internals: Machine-Independent Predicates"> +<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="Predicates.html#Predicates" rel="up" title="Predicates"> +<link href="Defining-Predicates.html#Defining-Predicates" rel="next" title="Defining Predicates"> +<link href="Predicates.html#Predicates" rel="previous" title="Predicates"> +<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="Machine_002dIndependent-Predicates"></a> +<div class="header"> +<p> +Next: <a href="Defining-Predicates.html#Defining-Predicates" accesskey="n" rel="next">Defining Predicates</a>, Up: <a href="Predicates.html#Predicates" accesskey="u" rel="up">Predicates</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="Machine_002dIndependent-Predicates-1"></a> +<h4 class="subsection">17.7.1 Machine-Independent Predicates</h4> +<a name="index-machine_002dindependent-predicates"></a> +<a name="index-generic-predicates"></a> + +<p>These are the generic predicates available to all back ends. They are +defined in <samp>recog.cc</samp>. The first category of predicates allow +only constant, or <em>immediate</em>, operands. +</p> +<dl> +<dt><a name="index-immediate_005foperand"></a>Function: <strong>immediate_operand</strong></dt> +<dd><p>This predicate allows any sort of constant that fits in <var>mode</var>. +It is an appropriate choice for instructions that take operands that +must be constant. +</p></dd></dl> + +<dl> +<dt><a name="index-const_005fint_005foperand"></a>Function: <strong>const_int_operand</strong></dt> +<dd><p>This predicate allows any <code>CONST_INT</code> expression that fits in +<var>mode</var>. It is an appropriate choice for an immediate operand that +does not allow a symbol or label. +</p></dd></dl> + +<dl> +<dt><a name="index-const_005fdouble_005foperand"></a>Function: <strong>const_double_operand</strong></dt> +<dd><p>This predicate accepts any <code>CONST_DOUBLE</code> expression that has +exactly <var>mode</var>. If <var>mode</var> is <code>VOIDmode</code>, it will also +accept <code>CONST_INT</code>. It is intended for immediate floating point +constants. +</p></dd></dl> + +<p>The second category of predicates allow only some kind of machine +register. +</p> +<dl> +<dt><a name="index-register_005foperand"></a>Function: <strong>register_operand</strong></dt> +<dd><p>This predicate allows any <code>REG</code> or <code>SUBREG</code> expression that +is valid for <var>mode</var>. It is often suitable for arithmetic +instruction operands on a RISC machine. +</p></dd></dl> + +<dl> +<dt><a name="index-pmode_005fregister_005foperand"></a>Function: <strong>pmode_register_operand</strong></dt> +<dd><p>This is a slight variant on <code>register_operand</code> which works around +a limitation in the machine-description reader. +</p> +<div class="smallexample"> +<pre class="smallexample">(match_operand <var>n</var> "pmode_register_operand" <var>constraint</var>) +</pre></div> + +<p>means exactly what +</p> +<div class="smallexample"> +<pre class="smallexample">(match_operand:P <var>n</var> "register_operand" <var>constraint</var>) +</pre></div> + +<p>would mean, if the machine-description reader accepted ‘<samp>:P</samp>’ +mode suffixes. Unfortunately, it cannot, because <code>Pmode</code> is an +alias for some other mode, and might vary with machine-specific +options. See <a href="Misc.html#Misc">Misc</a>. +</p></dd></dl> + +<dl> +<dt><a name="index-scratch_005foperand"></a>Function: <strong>scratch_operand</strong></dt> +<dd><p>This predicate allows hard registers and <code>SCRATCH</code> expressions, +but not pseudo-registers. It is used internally by <code>match_scratch</code>; +it should not be used directly. +</p></dd></dl> + +<p>The third category of predicates allow only some kind of memory reference. +</p> +<dl> +<dt><a name="index-memory_005foperand"></a>Function: <strong>memory_operand</strong></dt> +<dd><p>This predicate allows any valid reference to a quantity of mode +<var>mode</var> in memory, as determined by the weak form of +<code>GO_IF_LEGITIMATE_ADDRESS</code> (see <a href="Addressing-Modes.html#Addressing-Modes">Addressing Modes</a>). +</p></dd></dl> + +<dl> +<dt><a name="index-address_005foperand"></a>Function: <strong>address_operand</strong></dt> +<dd><p>This predicate is a little unusual; it allows any operand that is a +valid expression for the <em>address</em> of a quantity of mode +<var>mode</var>, again determined by the weak form of +<code>GO_IF_LEGITIMATE_ADDRESS</code>. To first order, if +‘<samp>(mem:<var>mode</var> (<var>exp</var>))<!-- /@w --></samp>’ is acceptable to +<code>memory_operand</code>, then <var>exp</var> is acceptable to +<code>address_operand</code>. Note that <var>exp</var> does not necessarily have +the mode <var>mode</var>. +</p></dd></dl> + +<dl> +<dt><a name="index-indirect_005foperand"></a>Function: <strong>indirect_operand</strong></dt> +<dd><p>This is a stricter form of <code>memory_operand</code> which allows only +memory references with a <code>general_operand</code> as the address +expression. New uses of this predicate are discouraged, because +<code>general_operand</code> is very permissive, so it’s hard to tell what +an <code>indirect_operand</code> does or does not allow. If a target has +different requirements for memory operands for different instructions, +it is better to define target-specific predicates which enforce the +hardware’s requirements explicitly. +</p></dd></dl> + +<dl> +<dt><a name="index-push_005foperand"></a>Function: <strong>push_operand</strong></dt> +<dd><p>This predicate allows a memory reference suitable for pushing a value +onto the stack. This will be a <code>MEM</code> which refers to +<code>stack_pointer_rtx</code>, with a side effect in its address expression +(see <a href="Incdec.html#Incdec">Incdec</a>); which one is determined by the +<code>STACK_PUSH_CODE</code> macro (see <a href="Frame-Layout.html#Frame-Layout">Frame Layout</a>). +</p></dd></dl> + +<dl> +<dt><a name="index-pop_005foperand"></a>Function: <strong>pop_operand</strong></dt> +<dd><p>This predicate allows a memory reference suitable for popping a value +off the stack. Again, this will be a <code>MEM</code> referring to +<code>stack_pointer_rtx</code>, with a side effect in its address +expression. However, this time <code>STACK_POP_CODE</code> is expected. +</p></dd></dl> + +<p>The fourth category of predicates allow some combination of the above +operands. +</p> +<dl> +<dt><a name="index-nonmemory_005foperand"></a>Function: <strong>nonmemory_operand</strong></dt> +<dd><p>This predicate allows any immediate or register operand valid for <var>mode</var>. +</p></dd></dl> + +<dl> +<dt><a name="index-nonimmediate_005foperand"></a>Function: <strong>nonimmediate_operand</strong></dt> +<dd><p>This predicate allows any register or memory operand valid for <var>mode</var>. +</p></dd></dl> + +<dl> +<dt><a name="index-general_005foperand"></a>Function: <strong>general_operand</strong></dt> +<dd><p>This predicate allows any immediate, register, or memory operand +valid for <var>mode</var>. +</p></dd></dl> + +<p>Finally, there are two generic operator predicates. +</p> +<dl> +<dt><a name="index-comparison_005foperator"></a>Function: <strong>comparison_operator</strong></dt> +<dd><p>This predicate matches any expression which performs an arithmetic +comparison in <var>mode</var>; that is, <code>COMPARISON_P</code> is true for the +expression code. +</p></dd></dl> + +<dl> +<dt><a name="index-ordered_005fcomparison_005foperator"></a>Function: <strong>ordered_comparison_operator</strong></dt> +<dd><p>This predicate matches any expression which performs an arithmetic +comparison in <var>mode</var> and whose expression code is valid for integer +modes; that is, the expression code will be one of <code>eq</code>, <code>ne</code>, +<code>lt</code>, <code>ltu</code>, <code>le</code>, <code>leu</code>, <code>gt</code>, <code>gtu</code>, +<code>ge</code>, <code>geu</code>. +</p></dd></dl> + +<hr> +<div class="header"> +<p> +Next: <a href="Defining-Predicates.html#Defining-Predicates" accesskey="n" rel="next">Defining Predicates</a>, Up: <a href="Predicates.html#Predicates" accesskey="u" rel="up">Predicates</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> |