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<h3 class="section">13.14 Declarations</h3>
<p><a name="index-RTL-declarations-3027"></a><a name="index-declarations_002c-RTL-3028"></a>
Declaration expression codes do not represent arithmetic operations
but rather state assertions about their operands.
<a name="index-strict_005flow_005fpart-3029"></a>
<a name="index-g_t_0040code_007bsubreg_007d_002c-in-_0040code_007bstrict_005flow_005fpart_007d-3030"></a>
<dl><dt><code>(strict_low_part (subreg:</code><var>m</var><code> (reg:</code><var>n</var> <var>r</var><code>) 0))</code><dd>This expression code is used in only one context: as the destination operand of a
<code>set</code> expression. In addition, the operand of this expression
must be a non-paradoxical <code>subreg</code> expression.
<p>The presence of <code>strict_low_part</code> says that the part of the
register which is meaningful in mode <var>n</var>, but is not part of
mode <var>m</var>, is not to be altered. Normally, an assignment to such
a subreg is allowed to have undefined effects on the rest of the
register when <var>m</var> is less than a word.
</dl>
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