<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 - [InstCombine] SimplifyAssociativeOrCommutative - dodgy NSW transform checks"
href="https://bugs.llvm.org/show_bug.cgi?id=43143">43143</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[InstCombine] SimplifyAssociativeOrCommutative - dodgy NSW transform checks
</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>Windows NT
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Scalar Optimizations
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>llvm-dev@redking.me.uk
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, Matthew.Arsenault@amd.com, spatel+llvm@rotateright.com
</td>
</tr></table>
<p>
<div>
<pre>The following code in InstructionCombining.cpp ~line 345 needs reviewing and
cleaning up:
if (IsNSW &&
(!Op0 || (isa<BinaryOperator>(Op0) && Op0->hasNoSignedWrap()))) {
// Note: this is only valid because SimplifyBinOp doesn't look at
// the operands to Op0.
I.setHasNoSignedWrap(true);
}
1 - Op0 came from dyn_cast<BinaryOperator>(I.getOperand(0)), and an outer if()
has already confirmed that its not null.
2 - Op0->hasNoSignedWrap does a cast<OverflowingBinaryOperator> which we're not
checking for.
I only noticed in passing as cppcheck warned that the !Op0 should be redundant.</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>