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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 - Memory SSA DSE regression - store after calloc not eliminated"
href="https://bugs.llvm.org/show_bug.cgi?id=50143">50143</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Memory SSA DSE regression - store after calloc not eliminated
</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>Linux
</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>david.bolvansky@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
<p>
<div>
<pre>#include <string.h>
#include <stdlib.h>
void * foo(long i) {
char *p = calloc(1, 10);
p[i] = 0;
return p;
}
LLVM 11 and lower:
define dso_local noalias i8* @foo(i64 %0) local_unnamed_addr #0 {
%2 = tail call noalias dereferenceable_or_null(10) i8* @calloc(i64 1, i64 10)
#2
ret i8* %2
}
LLVM 12+:
define dso_local noalias i8* @foo(i64 %0) local_unnamed_addr #0 {
%2 = tail call noalias dereferenceable_or_null(10) i8* @calloc(i64 1, i64 10)
#2
%3 = getelementptr inbounds i8, i8* %2, i64 %0
store i8 0, i8* %3, align 1, !tbaa !2
ret i8* %2
}</pre>
</div>
</p>
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