Conditional-Expressions.html 4.3 KB

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  69. <h4 class="subsection">11.6.3 Conditional Expressions</h4>
  70. <a name="index-Conditional-Expressions"></a>
  71. <p>A C <code>?:</code> expression is converted into an <code>if</code> statement with
  72. each branch assigning to the same temporary. So,
  73. </p>
  74. <div class="smallexample">
  75. <pre class="smallexample">a = b ? c : d;
  76. </pre></div>
  77. <p>becomes
  78. </p><div class="smallexample">
  79. <pre class="smallexample">if (b == 1)
  80. T1 = c;
  81. else
  82. T1 = d;
  83. a = T1;
  84. </pre></div>
  85. <p>The GIMPLE level if-conversion pass re-introduces <code>?:</code>
  86. expression, if appropriate. It is used to vectorize loops with
  87. conditions using vector conditional operations.
  88. </p>
  89. <p>Note that in GIMPLE, <code>if</code> statements are represented using
  90. <code>GIMPLE_COND</code>, as described below.
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