<html>
<head>
<base href="https://bugs.llvm.org/">
</head>
<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - SelectInst that replaces Or/And is not handled in SimplifyCFG"
href="https://bugs.llvm.org/show_bug.cgi?id=52065">52065</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>SelectInst that replaces Or/And is not handled in SimplifyCFG
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Miscellaneous Instrumentation passes
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>elena.demikhovsky@intel.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>Created <span class=""><a href="attachment.cgi?id=25323" name="attach_25323" title="Before simpilfycfg, demonstrates Select/Or/And missing optimization">attachment 25323</a> <a href="attachment.cgi?id=25323&action=edit" title="Before simpilfycfg, demonstrates Select/Or/And missing optimization">[details]</a></span>
Before simpilfycfg, demonstrates Select/Or/And missing optimization
The basic block with "or" is optimized in simplifycfg:
lor.lhs.false30: ; preds = %lor.lhs.false
%or.cond92 = or i1 %or.cond88, %cmp28
br i1 %or.cond92, label %if.end, label %if.then
while the same block with "select" is not optimized:
lor.lhs.false30: ; preds = %lor.lhs.false
%or.cond92 = select i1 %or.cond88, i1 true, i1 %cmp28
br i1 %or.cond92, label %if.end, label %if.then
This diff maybe considered as a fix:
llvm/lib/Transforms/Utils/SimplifyCFG.cpp:
< if (!Cond || (!isa<CmpInst>(Cond) && !isa<BinaryOperator>(Cond)) ||
---
<span class="quote">> auto isSelectAsBinaryOperator = [](Instruction *V) {
> return match(V, m_Select(m_Value(), m_Value(), m_Zero())) ||
> match(V, m_Select(m_Value(), m_One(), m_Value()));
> };
> if (!Cond ||
> (!isa<CmpInst>(Cond) && !isa<BinaryOperator>(Cond) &&
> !isSelectAsBinaryOperator(Cond)) ||</span ></pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>