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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 - Different codegen with/without -g"
href="https://bugs.llvm.org/show_bug.cgi?id=42138">42138</a>
</td>
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<tr>
<th>Summary</th>
<td>Different codegen with/without -g
</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>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>DebugInfo
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>chris.dawson@sony.com
</td>
</tr>
<tr>
<th>CC</th>
<td>jdevlieghere@apple.com, keith.walker@arm.com, llvm-bugs@lists.llvm.org, paul_robinson@playstation.sony.com
</td>
</tr></table>
<p>
<div>
<pre>Using the check-cfc tool (
<a href="https://github.com/llvm/llvm-project/tree/master/clang/utils/check_cfc">https://github.com/llvm/llvm-project/tree/master/clang/utils/check_cfc</a> ) to
spot a codegen difference depending on whether -g is specified or not.
$ cat PowerParser.ii.cc
template <typename, typename = int> class e;
class allocator {
public:
~allocator();
};
template <typename, typename> class e {
public:
e(char *, allocator = allocator());
};
template <typename b, typename c, typename d> bool operator==(e<c, d>, b);
class f {
public:
f(int *, int *, int *, int, int, int, int);
e<char> g();
void j();
};
int h, i;
class k {
void l();
bool m_fn4();
int m;
int n;
int q;
int fmap;
};
void k::l() {
e<char> o = "";
for (;;) {
int p = 0;
for (;;) {
if (m_fn4())
break;
f a(&q, &fmap, &m, n, h, i, 0);
if (a.g() == "")
a.j();
}
}
}
$ ./llvm-project/clang/utils/check_cfc/clang++ PowerParser.ii.cc -w -c -O1 -o
tmp.ll
Check CFC, checking: dash_g_no_change
PowerParser.ii.cc Code difference detected with -g
--- /tmp/tmpcdg_LH.o
+++ /tmp/tmpfkaPkW.o
@@ -19,6 +19,6 @@
28: 4c 8d 73 08 lea 0x8(%rbx),%r14
2c: 4c 8d 7b 0c lea 0xc(%rbx),%r15
30: 4c 8d 64 24 08 lea 0x8(%rsp),%r12
- 35: 66 2e 0f 1f 84 00 00 nopw %cs:0x0(%rax,%rax,1)
- 3c: 00 00 00
- 3f: 90 nop
+ 35: eb 09 jmp 40 <_ZN1k1lEv+0x40>
+ 37: 66 0f 1f 84 00 00 00 nopw 0x0(%rax,%rax,1)
+ 3e: 00 00
*** Diff truncated ***</pre>
</div>
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