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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 - [Analyzer][Z3] Wrong comparison operation being generated from ranged constraint"
href="https://bugs.llvm.org/show_bug.cgi?id=37855">37855</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>[Analyzer][Z3] Wrong comparison operation being generated from ranged constraint
</td>
</tr>
<tr>
<th>Product</th>
<td>clang
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>Linux
</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>
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<th>Component</th>
<td>Static Analyzer
</td>
</tr>
<tr>
<th>Assignee</th>
<td>dcoughlin@apple.com
</td>
</tr>
<tr>
<th>Reporter</th>
<td>mikhail.ramalho@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>The following program:
typedef struct o p;
struct o {
struct {
} s;
};
void q(*r, p2) {
r < p2;
}
void k(l, node) {
struct {
p *node;
} * n, *nodep, path[sizeof(void)];
path->node = l;
for (n = path; node != l;) {
q(node, n->node);
nodep = n;
}
if (nodep)
n[1].node->s;
}
generates the following constraint:
(conj_$1{struct o *}) - (reg_$3<int * r>): [-9223372036854775808, 0]
but the SMT generated is:
(and (bvuge (bvsub $1 $3) #x8000000000000000)
(bvule (bvsub $1 $3) #x0000000000000000))
The issue is that unsigned comparisons (bvuge and bvule) are being generated
instead of signed comparisons (bvsge and bvsle).
When generating the expressions:
(conj_$1{p *}) - (reg_$3<int * r>) >= -9223372036854775808
and
(conj_$1{p *}) - (reg_$3<int * r>) <= 0
both -9223372036854775808 and 0 are casted to pointer type and
LTy->isSignedIntegerOrEnumerationType() in Z3ConstraintManager::getZ3BinExpr
only checks if the type is signed, not if it's a pointer.</pre>
</div>
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