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<h3 class="section">Hints</h3>
<ul>
<li><cite>The extent to which suggestions made by using the </cite><code>register</code><cite>
storage-class specifier are effective (6.7.1).</cite>
<p>The <code>register</code> specifier affects code generation only in these ways:
<ul>
<li>When used as part of the register variable extension, see
<a href="Explicit-Reg-Vars.html#Explicit%20Reg%20Vars">Explicit Reg Vars</a>.
<li>When <code>-O0</code> is in use, the compiler allocates distinct stack
memory for all variables that do not have the <code>register</code>
storage-class specifier; if <code>register</code> is specified, the variable
may have a shorter lifespan than the code would indicate and may never
be placed in memory.
<li>On some rare x86 targets, <code>setjmp</code> doesn't save the registers in
all circumstances. In those cases, GCC doesn't allocate any variables
in registers unless they are marked <code>register</code>.
</ul>
<li><cite>The extent to which suggestions made by using the inline function
specifier are effective (6.7.4).</cite>
<p>GCC will not inline any functions if the <code>-fno-inline</code> option is
used or if <code>-O0</code> is used. Otherwise, GCC may still be unable to
inline a function for many reasons; the <code>-Winline</code> option may be
used to determine if a function has not been inlined and why not.
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