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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - LLVM 10 regression in comparison of gep inbounds difference"
href="https://bugs.llvm.org/show_bug.cgi?id=44419">44419</a>
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<th>Summary</th>
<td>LLVM 10 regression in comparison of gep inbounds difference
</td>
</tr>
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<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>All
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Scalar Optimizations
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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</tr>
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<th>Reporter</th>
<td>nikita.ppv@gmail.com
</td>
</tr>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>define i1 @test([0 x i32]* nonnull %arg, i64 %arg1, i64 %arg2) {
%tmp = getelementptr inbounds [0 x i32], [0 x i32]* %arg, i64 0, i64 0
%tmp3 = getelementptr inbounds [0 x i32], [0 x i32]* %arg, i64 0, i64 %arg1
%tmp6 = ptrtoint i32* %tmp3 to i64
%tmp7 = ptrtoint i32* %tmp to i64
%tmp8 = sub nuw i64 %tmp6, %tmp7
%tmp9 = lshr exact i64 %tmp8, 2
%tmp24 = icmp ugt i64 %tmp9, %arg2
ret i1 %tmp24
}
opt -instcombine on LLVM 9:
define i1 @test([0 x i32]* nonnull %arg, i64 %arg1, i64 %arg2) {
%tmp24 = icmp ugt i64 %arg1, %arg2
ret i1 %tmp24
}
opt -instcombine on LLVM 10:
define i1 @test([0 x i32]* nonnull %arg, i64 %arg1, i64 %arg2) {
%tmp3.idx = and i64 %arg1, 4611686018427387903
%tmp24 = icmp ugt i64 %tmp3.idx, %arg2
ret i1 %tmp24
}
Am I missing some subtlety here that prevents inbounds from implying that the
masking is unnecessary?</pre>
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