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<base href="https://bugs.llvm.org/">
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<body><table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Simple intraprocedural DSE"
href="https://bugs.llvm.org/show_bug.cgi?id=51963">51963</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Simple intraprocedural DSE
</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>__attribute__ ((noinline))
void
copy (int *a, int *b)
{
*a=*b;
}
void foo(int b)
{
int a = 42;
copy (&a,&b);
}
foo: # @foo
push rax
mov dword ptr [rsp + 4], edi
mov dword ptr [rsp], 42 <------- Useless store
mov rdi, rsp
lea rsi, [rsp + 4]
call copy
pop rax
ret
int p,q;
__attribute__ ((noinline, noclone))
int
test (int *p)
{
*p = 1;
}
int
test1()
{
q = 123;
test(&p);
return q;
}
test1: # @test1
push rax
mov dword ptr [rip + q], 123
mov edi, offset p
call test
mov eax, dword ptr [rip + q] // Can be mov eax, 123
pop rcx
ret</pre>
</div>
</p>
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