| <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> |
| <html> |
| <!-- Copyright (C) 1988-2015 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 5.2, http://www.gnu.org/software/texinfo/ --> |
| <head> |
| <title>GNU Compiler Collection (GCC) Internals: Define Subst Pattern Matching</title> |
| |
| <meta name="description" content="GNU Compiler Collection (GCC) Internals: Define Subst Pattern Matching"> |
| <meta name="keywords" content="GNU Compiler Collection (GCC) Internals: Define Subst Pattern Matching"> |
| <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="Define-Subst.html#Define-Subst" rel="up" title="Define Subst"> |
| <link href="Define-Subst-Output-Template.html#Define-Subst-Output-Template" rel="next" title="Define Subst Output Template"> |
| <link href="Define-Subst-Example.html#Define-Subst-Example" rel="prev" title="Define Subst Example"> |
| <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="Define-Subst-Pattern-Matching"></a> |
| <div class="header"> |
| <p> |
| Next: <a href="Define-Subst-Output-Template.html#Define-Subst-Output-Template" accesskey="n" rel="next">Define Subst Output Template</a>, Previous: <a href="Define-Subst-Example.html#Define-Subst-Example" accesskey="p" rel="prev">Define Subst Example</a>, Up: <a href="Define-Subst.html#Define-Subst" accesskey="u" rel="up">Define Subst</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="Pattern-Matching-in-define_005fsubst"></a> |
| <h4 class="subsection">16.21.2 Pattern Matching in <code>define_subst</code></h4> |
| <a name="index-define_005fsubst-2"></a> |
| |
| <p>All expressions, allowed in <code>define_insn</code> or <code>define_expand</code>, |
| are allowed in the input-template of <code>define_subst</code>, except |
| <code>match_par_dup</code>, <code>match_scratch</code>, <code>match_parallel</code>. The |
| meanings of expressions in the input-template were changed: |
| </p> |
| <p><code>match_operand</code> matches any expression (possibly, a subtree in |
| RTL-template), if modes of the <code>match_operand</code> and this expression |
| are the same, or mode of the <code>match_operand</code> is <code>VOIDmode</code>, or |
| this expression is <code>match_dup</code>, <code>match_op_dup</code>. If the |
| expression is <code>match_operand</code> too, and predicate of |
| <code>match_operand</code> from the input pattern is not empty, then the |
| predicates are compared. That can be used for more accurate filtering |
| of accepted RTL-templates. |
| </p> |
| <p><code>match_operator</code> matches common operators (like <code>plus</code>, |
| <code>minus</code>), <code>unspec</code>, <code>unspec_volatile</code> operators and |
| <code>match_operator</code>s from the original pattern if the modes match and |
| <code>match_operator</code> from the input pattern has the same number of |
| operands as the operator from the original pattern. |
| </p> |
| |
| |
| |
| </body> |
| </html> |
