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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Minor code gen difference between debug and no-debug introduced by X86FixupSetCC."
href="https://bugs.llvm.org/show_bug.cgi?id=33866">33866</a>
</td>
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<th>Summary</th>
<td>Minor code gen difference between debug and no-debug introduced by X86FixupSetCC.
</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>
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<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>Backend: X86
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>Wolfgang_Pieb@playstation.sony.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
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<pre>Created <span class=""><a href="attachment.cgi?id=18824" name="attach_18824" title="Test source (random generated and reduced).">attachment 18824</a> <a href="attachment.cgi?id=18824&action=edit" title="Test source (random generated and reduced).">[details]</a></span>
Test source (random generated and reduced).
The attached C++ source exhibits a subtle difference in code gen
when compiled with -g vs. without it. Nothing particularly important,
but probably caused by the presence of DBG_VALUE instructions.
Compile with clang with -O2 and with -O2 -g and diff the objdump -d
output:
58,70c58,70
< a9: 8a 0d 00 00 00 00 mov 0x0(%rip),%cl # af
<_Z6test30v+0xaf>
< af: 31 c0 xor %eax,%eax
< b1: 0a 4c 24 1e or 0x1e(%rsp),%cl
< b5: 0f 28 05 00 00 00 00 movaps 0x0(%rip),%xmm0 # bc
<_Z6test30v+0xbc>
< bc: 0f 29 44 24 20 movaps %xmm0,0x20(%rsp)
< c1: 0f 28 05 00 00 00 00 movaps 0x0(%rip),%xmm0 # c8
<_Z6test30v+0xc8>
< c8: 0f 29 44 24 30 movaps %xmm0,0x30(%rsp)
< cd: 0f 95 c1 setne %cl
< d0: 74 33 je 105 <_Z6test30v+0x105>
< d2: 88 c8 mov %cl,%al
< d4: b1 01 mov $0x1,%cl
< d6: 0f 57 c0 xorps %xmm0,%xmm0
< d9: 0f 1f 80 00 00 00 00 nopl 0x0(%rax)
---
<span class="quote">> a9: 8a 05 00 00 00 00 mov 0x0(%rip),%al # af <_Z6test30v+0xaf>
> af: 0a 44 24 1e or 0x1e(%rsp),%al
> b3: 0f 28 05 00 00 00 00 movaps 0x0(%rip),%xmm0 # ba <_Z6test30v+0xba>
> ba: 0f 29 44 24 20 movaps %xmm0,0x20(%rsp)
> bf: 0f 28 05 00 00 00 00 movaps 0x0(%rip),%xmm0 # c6 <_Z6test30v+0xc6>
> c6: 0f 29 44 24 30 movaps %xmm0,0x30(%rsp)
> cb: 0f 95 c0 setne %al
> ce: 74 35 je 105 <_Z6test30v+0x105>
> d0: 0f b6 c0 movzbl %al,%eax
> d3: b1 01 mov $0x1,%cl
> d5: 0f 57 c0 xorps %xmm0,%xmm0
> d8: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1)
> df: 00</span ></pre>
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