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<base href="https://llvm.org/bugs/" />
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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 --- - Shrink-wrapping clobbers live EFLAGS value"
href="https://llvm.org/bugs/show_bug.cgi?id=27531">27531</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Shrink-wrapping clobbers live EFLAGS value
</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>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Common Code Generator Code
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>hans@chromium.org
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, qcolombet@apple.com
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>a.cc:
struct S {
void foo();
void bar(const int*, double*);
int x_;
};
void S::foo() {
int data[] = { x_ > 32 ? 42 : 128 };
if (x_ <= 31)
return;
double d;
bar(data, &d);
}
Compiled like this:
$ bin/clang -target i686-pc-win32 -Os -S -o - /tmp/a.cc -march=i686
Yields the following output:
"?foo@S@@QAEXXZ": # @"\01?foo@S@@QAEXXZ"
# BB#0: # %entry
cmpl $32, (%ecx)
movl $42, %eax
jg LBB0_2 <---- Sets EFLAGS
# BB#1: # %entry
movl $128, %eax
LBB0_2: # %entry
pushl %ebp
movl %esp, %ebp
andl $-8, %esp <---- Clobbers EFLAGS
leal -16(%esp), %esp
movl %eax, 4(%esp)
jl LBB0_4 <---- Was depending on EFLAGS
# BB#3: # %if.end
leal 8(%esp), %eax
leal 4(%esp), %edx
pushl %eax
pushl %edx
calll "?bar@S@@QAEXPBHPAN@Z"
LBB0_4: # %cleanup
movl %ebp, %esp
popl %ebp
retl</pre>
</div>
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