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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [SVE] Don't generate whilelo instruction to enhance the loop condition"
href="https://bugs.llvm.org/show_bug.cgi?id=52386">52386</a>
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<th>Summary</th>
<td>[SVE] Don't generate whilelo instruction to enhance the loop condition
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<th>Product</th>
<td>libraries
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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>Windows NT
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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>Backend: AArch64
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>zhongyunde@huawei.com
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<th>CC</th>
<td>arnaud.degrandmaison@arm.com, llvm-bugs@lists.llvm.org, smithp352@googlemail.com, Ties.Stuij@arm.com
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<p>
<div>
<pre>case from <a href="https://reviews.llvm.org/D91077">https://reviews.llvm.org/D91077</a>, with this simple case, the newest
clang will not generate whilelo insn for SVE to control the loop condition
(<a href="https://godbolt.org/z/hTf5bnhxW">https://godbolt.org/z/hTf5bnhxW</a>, used normal compare insn), while gcc can
(<a href="https://godbolt.org/z/xq4vdEYPY">https://godbolt.org/z/xq4vdEYPY</a>, used whilelo insn).
void loop(int N, double *a, double *b) {
#pragma clang loop vectorize_width(4, scalable)
for (int i = 0; i < N; i++) {
a[i] = b[i] + 1.0;
}
}</pre>
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