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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 translation of minnum with nnan flag"
href="https://bugs.llvm.org/show_bug.cgi?id=45478">45478</a>
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<th>Summary</th>
<td>Incorrect translation of minnum with nnan flag
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
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<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>
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<th>Severity</th>
<td>normal
</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>liuz@cs.utah.edu
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>As stated in LangRef, if either operand for llvm.minnum is a NaN, returns the
other non-NaN operand. If llvm.minnum is attached with nnan flag, when an
argument is a NaN, it produces a poison value.
See below the incorrect transformation. When input %x is NaN, the source
program returns 0.0, while the target program returns poison. Target is more
poisonous than source.
llvm/test/Transforms/InstCombine/minnum.ll
define float @minnum_f32_1_minnum_p0_val_nnan_ninf(float %x) {
; CHECK-LABEL: @minnum_f32_1_minnum_p0_val_nnan_ninf(
; CHECK-NEXT: [[TMP1:%.*]] = call nnan ninf float @llvm.minnum.f32(float
[[X:%.*]], float 0.000000e+00)
; CHECK-NEXT: ret float [[TMP1]]
;
%y = call float @llvm.minnum.f32(float 0.0, float %x)
%z = call nnan ninf float @llvm.minnum.f32(float %y, float 1.0)
ret float %z
}</pre>
</div>
</p>
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