visus
/
toolchain-gcc-arm-embedded
Tarkkaile 1
Äänestä 0
Fork 0
Koodi Ongelmat 0 Pull-pyynnöt 0 Julkaisut 0 Wiki Activity
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
2 Commitit
1 Haara
Haara: main
Branchit Tagit
${ item.name }
Create branch ${ searchTerm }
from 'main'
${ noResults }
toolchain-gcc-arm-embedded/share/doc/gcc-arm-none-eabi/html/gccint/Comparisons-involving-poly_...

128 lines
7.5KB
Raaka Pysyvä linkki Blame Historia 

  1. <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">

  2. <html>

  3. <!-- Copyright (C) 1988-2020 Free Software Foundation, Inc.

  4. 

  5. Permission is granted to copy, distribute and/or modify this document

  6. under the terms of the GNU Free Documentation License, Version 1.3 or

  7. any later version published by the Free Software Foundation; with the

  8. Invariant Sections being "Funding Free Software", the Front-Cover

  9. Texts being (a) (see below), and with the Back-Cover Texts being (b)

  10. (see below).  A copy of the license is included in the section entitled

  11. "GNU Free Documentation License".

  12. 

  13. (a) The FSF's Front-Cover Text is:

  14. 

  15. A GNU Manual

  16. 

  17. (b) The FSF's Back-Cover Text is:

  18. 

  19. You have freedom to copy and modify this GNU Manual, like GNU

  20.      software.  Copies published by the Free Software Foundation raise

  21.      funds for GNU development. -->

  22. <!-- Created by GNU Texinfo 6.5, http://www.gnu.org/software/texinfo/ -->

  23. <head>

  24. <meta http-equiv="Content-Type" content="text/html; charset=utf-8">

  25. <title>Comparisons involving poly_int (GNU Compiler Collection (GCC) Internals)</title>

  26. 

  27. <meta name="description" content="Comparisons involving poly_int (GNU Compiler Collection (GCC) Internals)">

  28. <meta name="keywords" content="Comparisons involving poly_int (GNU Compiler Collection (GCC) Internals)">

  29. <meta name="resource-type" content="document">

  30. <meta name="distribution" content="global">

  31. <meta name="Generator" content="makeinfo">

  32. <link href="index.html#Top" rel="start" title="Top">

  33. <link href="Option-Index.html#Option-Index" rel="index" title="Option Index">

  34. <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">

  35. <link href="poly_005fint.html#poly_005fint" rel="up" title="poly_int">

  36. <link href="Comparison-functions-for-poly_005fint.html#Comparison-functions-for-poly_005fint" rel="next" title="Comparison functions for poly_int">

  37. <link href="Consequences-of-using-poly_005fint.html#Consequences-of-using-poly_005fint" rel="prev" title="Consequences of using poly_int">

  38. <style type="text/css">

  39. <!--

  40. a.summary-letter {text-decoration: none}

  41. blockquote.indentedblock {margin-right: 0em}

  42. blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}

  43. blockquote.smallquotation {font-size: smaller}

  44. div.display {margin-left: 3.2em}

  45. div.example {margin-left: 3.2em}

  46. div.lisp {margin-left: 3.2em}

  47. div.smalldisplay {margin-left: 3.2em}

  48. div.smallexample {margin-left: 3.2em}

  49. div.smalllisp {margin-left: 3.2em}

  50. kbd {font-style: oblique}

  51. pre.display {font-family: inherit}

  52. pre.format {font-family: inherit}

  53. pre.menu-comment {font-family: serif}

  54. pre.menu-preformatted {font-family: serif}

  55. pre.smalldisplay {font-family: inherit; font-size: smaller}

  56. pre.smallexample {font-size: smaller}

  57. pre.smallformat {font-family: inherit; font-size: smaller}

  58. pre.smalllisp {font-size: smaller}

  59. span.nolinebreak {white-space: nowrap}

  60. span.roman {font-family: initial; font-weight: normal}

  61. span.sansserif {font-family: sans-serif; font-weight: normal}

  62. ul.no-bullet {list-style: none}

  63. -->

  64. </style>

  65. 

  66. 

  67. </head>

  68. 

  69. <body lang="en">

  70. <a name="Comparisons-involving-poly_005fint"></a>

  71. <div class="header">

  72. <p>

  73. Next: <a href="Arithmetic-on-poly_005fints.html#Arithmetic-on-poly_005fints" accesskey="n" rel="next">Arithmetic on <code>poly_int</code>s</a>, Previous: <a href="Consequences-of-using-poly_005fint.html#Consequences-of-using-poly_005fint" accesskey="p" rel="prev">Consequences of using <code>poly_int</code></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>

  74. </div>

  75. <hr>

  76. <a name="Comparisons-involving-poly_005fint-1"></a>

  77. <h3 class="section">10.3 Comparisons involving <code>poly_int</code></h3>

  78. 

  79. <p>In general we need to compare sizes and offsets in two situations:

  80. those in which the values need to be ordered, and those in which

  81. the values can be unordered.  More loosely, the distinction is often

  82. between values that have a definite link (usually because they refer to the

  83. same underlying register or memory location) and values that have

  84. no definite link.  An example of the former is the relationship between

  85. the inner and outer sizes of a subreg, where we must know at compile time

  86. whether the subreg is paradoxical, partial, or complete.  An example of

  87. the latter is alias analysis: we might want to check whether two

  88. arbitrary memory references overlap.

  89. </p>

  90. <p>Referring back to the examples in the previous section, it makes sense

  91. to ask whether a memory reference of size &lsquo;<samp>3 + 4<var>x</var></samp>&rsquo; overlaps

  92. one of size &lsquo;<samp>1 + 5<var>x</var></samp>&rsquo;, but it does not make sense to have a

  93. subreg in which the outer mode has &lsquo;<samp>3 + 4<var>x</var></samp>&rsquo; bytes and the

  94. inner mode has &lsquo;<samp>1 + 5<var>x</var></samp>&rsquo; bytes (or vice versa).  Such subregs

  95. are always invalid and should trigger an internal compiler error

  96. if formed.

  97. </p>

  98. <p>The underlying operators are the same in both cases, but the distinction

  99. affects how they are used.

  100. </p>

  101. <table class="menu" border="0" cellspacing="0">

  102. <tr><td align="left" valign="top">&bull; <a href="Comparison-functions-for-poly_005fint.html#Comparison-functions-for-poly_005fint" accesskey="1">Comparison functions for <code>poly_int</code></a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">

  103. </td></tr>

  104. <tr><td align="left" valign="top">&bull; <a href="Properties-of-the-poly_005fint-comparisons.html#Properties-of-the-poly_005fint-comparisons" accesskey="2">Properties of the <code>poly_int</code> comparisons</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">

  105. </td></tr>

  106. <tr><td align="left" valign="top">&bull; <a href="Comparing-potentially_002dunordered-poly_005fints.html#Comparing-potentially_002dunordered-poly_005fints" accesskey="3">Comparing potentially-unordered <code>poly_int</code>s</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">

  107. </td></tr>

  108. <tr><td align="left" valign="top">&bull; <a href="Comparing-ordered-poly_005fints.html#Comparing-ordered-poly_005fints" accesskey="4">Comparing ordered <code>poly_int</code>s</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">

  109. </td></tr>

  110. <tr><td align="left" valign="top">&bull; <a href="Checking-for-a-poly_005fint-marker-value.html#Checking-for-a-poly_005fint-marker-value" accesskey="5">Checking for a <code>poly_int</code> marker value</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">

  111. </td></tr>

  112. <tr><td align="left" valign="top">&bull; <a href="Range-checks-on-poly_005fints.html#Range-checks-on-poly_005fints" accesskey="6">Range checks on <code>poly_int</code>s</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">

  113. </td></tr>

  114. <tr><td align="left" valign="top">&bull; <a href="Sorting-poly_005fints.html#Sorting-poly_005fints" accesskey="7">Sorting <code>poly_int</code>s</a>:</td><td>&nbsp;&nbsp;</td><td align="left" valign="top">

  115. </td></tr>

  116. </table>

  117. 

  118. <hr>

  119. <div class="header">

  120. <p>

  121. Next: <a href="Arithmetic-on-poly_005fints.html#Arithmetic-on-poly_005fints" accesskey="n" rel="next">Arithmetic on <code>poly_int</code>s</a>, Previous: <a href="Consequences-of-using-poly_005fint.html#Consequences-of-using-poly_005fint" accesskey="p" rel="prev">Consequences of using <code>poly_int</code></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>

  122. </div>

  123. 

  124. 

  125. 

  126. </body>

  127. </html>