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<base href="http://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - i8 checked mul is wrong on x86"
href="http://llvm.org/bugs/show_bug.cgi?id=19858">19858</a>
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<tr>
<th>Summary</th>
<td>i8 checked mul is wrong on x86
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>All
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>Backend: X86
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>kfischer@college.harvard.edu
</td>
</tr>
<tr>
<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
</td>
</tr>
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Consider the following code sample:
declare {i8, i1} @llvm.umul.with.overflow.i8(i8 %a, i8 %b)
define i8 @main(i32 %argc) {
top:
%RHS = trunc i32 %argc to i8
%umul = call { i8, i1 } @llvm.umul.with.overflow.i8(i8 25, i8 %RHS)
%ex = extractvalue { i8, i1 } %umul, 1
br i1 %ex, label %L, label %L1
L: ; preds = %top
ret i8 %RHS
L1: ; preds = %top
%umul.value = extractvalue { i8, i1 } %umul, 0
ret i8 %umul.value
}
Running this with `lli test.ll` gives a return value of 1 rather than 25 (i.e.
the overflow flag was set when it shouldn't have been.</pre>
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