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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Optimize switch over fields of homogeneous struct into pointer arithmetic"
href="https://bugs.llvm.org/show_bug.cgi?id=34285">34285</a>
</td>
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<th>Summary</th>
<td>Optimize switch over fields of homogeneous struct into pointer arithmetic
</td>
</tr>
<tr>
<th>Product</th>
<td>new-bugs
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>new bugs
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>arcata@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>In the following IR, the switch arms could be optimized away into a dynamic gep
into the homogeneous struct, but this does not happen:
%equistruct = type { i32, i32, i32, i32 }
declare void @llvm.trap() noreturn nounwind
define void @index(%equistruct* %a, i32 %b, i32 %c) {
entry:
switch i32 %b, label %default [
i32 0, label %i0
i32 1, label %i1
i32 2, label %i2
i32 3, label %i3
]
i0:
%d0 = getelementptr %equistruct, %equistruct* %a, i32 0, i32 0
store i32 %c, i32* %d0
ret void
i1:
%d1 = getelementptr %equistruct, %equistruct* %a, i32 0, i32 1
store i32 %c, i32* %d1
ret void
i2:
%d2 = getelementptr %equistruct, %equistruct* %a, i32 0, i32 2
store i32 %c, i32* %d2
ret void
i3:
%d3 = getelementptr %equistruct, %equistruct* %a, i32 0, i32 3
store i32 %c, i32* %d3
ret void
default:
call void @llvm.trap()
unreachable
}</pre>
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