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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 - Incorrect instcombine 'and + icmp eq' -> 'icmp ult' fold"
href="https://bugs.llvm.org/show_bug.cgi?id=43731">43731</a>
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<th>Summary</th>
<td>Incorrect instcombine 'and + icmp eq' -> 'icmp ult' fold
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<th>Product</th>
<td>libraries
</td>
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<th>Version</th>
<td>trunk
</td>
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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>
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<th>Keywords</th>
<td>miscompilation
</td>
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Scalar Optimizations
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>nunoplopes@sapo.pt
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<th>CC</th>
<td>lebedev.ri@gmail.com, llvm-bugs@lists.llvm.org, regehr@cs.utah.edu, spatel+llvm@rotateright.com
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<pre>The 2nd element of the result of this test case is incorrect
(InstCombine/canonicalize-constant-low-bit-mask-and-icmp-eq-to-icmp-ule.ll):
define <3 x i1> @p3_vec_splat_undef(<3 x i8> %x) {
%tmp0 = and <3 x i8> %x, { 3, undef, 3 }
%ret = icmp eq <3 x i8> %tmp0, %x
ret <3 x i1> %ret
}
=>
define <3 x i1> @p3_vec_splat_undef(<3 x i8> %x) {
%1 = icmp ult <3 x i8> %x, { 4, undef, 4 }
ret <3 x i1> %1
}
Transformation doesn't verify!
ERROR: Value mismatch
Example:
<3 x i8> %x = < #x00 (0), #x00 (0), #x00 (0) >
Source:
<3 x i8> %tmp0 = < #x00 (0), #x00 (0), #x00 (0) >
<3 x i1> %ret = < #x1 (1), #x1 (1), #x1 (1) >
Target:
<3 x i1> %1 = < #x1 (1), #x0 (0), #x1 (1) >
Source value: < #x1 (1), #x1 (1), #x1 (1) >
Target value: < #x1 (1), #x0 (0), #x1 (1) ></pre>
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