<html>
<head>
<base href="https://llvm.org/bugs/" />
</head>
<body><span class="vcard"><a class="email" href="mailto:sanjoy@playingwithpointers.com" title="Sanjoy Das <sanjoy@playingwithpointers.com>"> <span class="fn">Sanjoy Das</span></a>
</span> changed
<a class="bz_bug_link
bz_status_REOPENED "
title="REOPENED --- - wrong code at -O1 and above on x86_64-linux-gnu"
href="https://llvm.org/bugs/show_bug.cgi?id=27002">bug 27002</a>
<br>
<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>What</th>
<th>Removed</th>
<th>Added</th>
</tr>
<tr>
<td style="text-align:right;">Status</td>
<td>RESOLVED
</td>
<td>REOPENED
</td>
</tr>
<tr>
<td style="text-align:right;">Resolution</td>
<td>INVALID
</td>
<td>---
</td>
</tr></table>
<p>
<div>
<b><a class="bz_bug_link
bz_status_REOPENED "
title="REOPENED --- - wrong code at -O1 and above on x86_64-linux-gnu"
href="https://llvm.org/bugs/show_bug.cgi?id=27002#c3">Comment # 3</a>
on <a class="bz_bug_link
bz_status_REOPENED "
title="REOPENED --- - wrong code at -O1 and above on x86_64-linux-gnu"
href="https://llvm.org/bugs/show_bug.cgi?id=27002">bug 27002</a>
from <span class="vcard"><a class="email" href="mailto:sanjoy@playingwithpointers.com" title="Sanjoy Das <sanjoy@playingwithpointers.com>"> <span class="fn">Sanjoy Das</span></a>
</span></b>
<pre>(In reply to <a href="show_bug.cgi?id=27002#c2">comment #2</a>)
<span class="quote">> This behavior is intentional and is a result of clang's implementation of
> the previsions of the C++ standard.
>
> C++14 [expr.new]p10:
> "An implementation is allowed to omit a call to a replaceable global
> allocation function [...]."</span >
In the above specific case the behavior may be fine, since we delete both
the new and the delete; but how about something like
extern "C" void _exit (int);
void operator delete (void *p) throw () {
_exit (0);
}
void foo(int **escape_loc) {
int *i = new int;
*escape_loc = i;
delete i;
}
?
clang today compiles foo to
define void @_Z3fooPPi(i32** nocapture %escape_loc) #2 {
entry:
%call = tail call noalias i8* @_Znwm(i64 4) #5
%0 = bitcast i32** %escape_loc to i8**
store i8* %call, i8** %0, align 8, !tbaa !2
ret void
}
i.e. elides the deallocation, but not the allocation, and in
expr.delete[7] we have
"If the allocation call for the new-expression for the object to be
deleted was not omitted (5.3.4), the delete-expression shall call a
deallocation function (3.7.4.2). The value returned from the
allocation call of the new-expression shall be passed as the first
argument to the deallocation function."</pre>
</div>
</p>
<hr>
<span>You are receiving this mail because:</span>
<ul>
<li>You are on the CC list for the bug.</li>
</ul>
</body>
</html>