at setting an optimization level
overrides all earlier flags.
</p>
<p>
Here are the available flags and at what optimization levels they
are enabled:
</p>
<table class="opt">
<tr class="opthead">
<td class="flag_name">Flag</td>
<td class="flag_level">-O1</td>
<td class="flag_level">-O2</td>
<td class="flag_level">-O3</td>
<td class="flag_desc">&nbsp;</td>
</tr>
<tr class="odd separate">
<td class="flag_name">fold</td><td class="flag_level">&bull;</td><td class="flag_level">&bull;</td><td class="flag_level">