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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [GlobalISel][AArch64] Two load instructions generated for single volatile load"
href="https://bugs.llvm.org/show_bug.cgi?id=36018">36018</a>
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<th>Summary</th>
<td>[GlobalISel][AArch64] Two load instructions generated for single volatile load
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<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>GlobalISel
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>john.brawn.123@gmail.com
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</tr>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<p>
<div>
<pre>For the following IR:
@g = global i16 0, align 2
declare void @bar(i32)
define hidden void @foo() {
%1 = load volatile i16, i16* @g, align 2
%2 = sext i16 %1 to i32
call void @bar(i32 %2)
ret void
}
llc -mtriple=aarch64 -global-isel generates for the load followed by sext:
adrp x8, g
add x8, x8, :lo12:g
ldrh wzr, [x8]
ldrsh w0, [x8]
g is loaded twice, once with a zero-extending load which is discarded, and
second with a sign-extending load. For a volatile load we should be generating
only a single load instruction.</pre>
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