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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 - [AArch64] copy incorrectly erased and discard zero-extend operation"
href="https://bugs.llvm.org/show_bug.cgi?id=48066">48066</a>
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<th>Summary</th>
<td>[AArch64] copy incorrectly erased and discard zero-extend operation
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>All
</td>
</tr>
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<th>OS</th>
<td>Linux
</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>
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<th>Component</th>
<td>Backend: AArch64
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>chengeng5@huawei.com
</td>
</tr>
<tr>
<th>CC</th>
<td>arnaud.degrandmaison@arm.com, llvm-bugs@lists.llvm.org, smithp352@googlemail.com, Ties.Stuij@arm.com
</td>
</tr></table>
<p>
<div>
<pre>$ clang -O3 test-case.ll -w ;./a.out
c = -8917
$ clang -O0 test-case.ll -w ;./a.out
c = 4294958379
@b = dso_local local_unnamed_addr global { [3 x i8], i8, i8, i8, i8, i8 } { [3
x i8] undef, i8 -64, i8 74, i8 -9, i8 -1, i8 7 }, align 8
@c = common dso_local local_unnamed_addr global i64 0, align 8
@.str = private unnamed_addr constant [9 x i8] c"c = %ld\0A\00", align 1
define dso_local i8 @d(i64 %h) local_unnamed_addr {
entry:
ret i8 undef
}
declare dso_local i32 @printf(i8* nocapture readonly, ...) local_unnamed_addr
define dso_local i32 @main() local_unnamed_addr {
entry:
%bf.load = load i64, i64* bitcast ({ [3 x i8], i8, i8, i8, i8, i8 }* @b to
i64*), align 8
%0 = lshr i64 %bf.load, 30
%sext3 = shl nuw nsw i64 %0, 16
%sext = trunc i64 %sext3 to i32
%conv.i = ashr exact i32 %sext, 16
%conv.i.i = zext i32 %conv.i to i64
store i64 %conv.i.i, i64* @c, align 8
%call.i.i = tail call i32 (i8*, ...) @printf(i8* nonnull dereferenceable(1)
getelementptr inbounds ([9 x i8], [9 x i8]* @.str, i64 0, i64 0), i64
%conv.i.i)
%call4.i = tail call i8 bitcast (i8 (i64)* @d to i8 (i32, i32)*)(i32 0, i32
%conv.i)
ret i32 0
}</pre>
</div>
</p>
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