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<base href="https://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - mldst-motion miscompile with call to exit()"
href="https://llvm.org/bugs/show_bug.cgi?id=27858">27858</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>mldst-motion miscompile with call to exit()
</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>normal
</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>eli.friedman@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>Testcase:
#include <stdlib.h>
void f() { exit(1); }
void (*ff)() = f;
int r, s;
void g(int a, int*restrict p) {
if (a) {ff(); r = p[1]; }
else { s = p[1]; }
}
void (*gg)(int, int*restrict) = g;
int main() {
gg(1, 0);
}
Works with gcc or clang -O0, crashes with clang -O2.
Testcase:
#include <stdlib.h>
#include <stdio.h>
void f() { throw 1; }
void (*ff)() = f;
void f2() {}
void (*ff2)() = f2;
int r, s;
void g(int a, int*__restrict p) {
if (a) { ff2(); p[1] = 2; ff(); }
else { p[1] = 2; }
}
void (*gg)(int, int*restrict) = g;
int main() {
int a[2] = {0};
try {
gg(1, a);
} catch (...) {}
if (a[1] != 2) abort();
}
Works with gcc or clang -O0, aborts with clang -O2.
I think the problem is
MergedLoadStoreMotion::isLoadHoistBarrierInRange/isStoreSinkBarrierInRange; you
can't use alias analysis to prove that a pointer is valid.
(Artificial testcases.)</pre>
</div>
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