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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - clang-cl "cannot mangle this built-in __float128 type" due to promotions"
href="https://bugs.llvm.org/show_bug.cgi?id=35174">35174</a>
</td>
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<th>Summary</th>
<td>clang-cl "cannot mangle this built-in __float128 type" due to promotions
</td>
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<th>Product</th>
<td>clang
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
</tr>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>enhancement
</td>
</tr>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>C++
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>hans@chromium.org
</td>
</tr>
<tr>
<th>CC</th>
<td>dgregor@apple.com, llvm-bugs@lists.llvm.org, richard-llvm@metafoo.co.uk, rnk@google.com
</td>
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<pre>$ cat /tmp/a.cc
template <bool> struct B;
template <class T> constexpr bool is_floating_point_v = false;
struct StrictNumeric {
StrictNumeric(int);
template <typename Dst, B<is_floating_point_v<Dst>> = nullptr> operator
Dst();
};
static_assert(StrictNumeric(1) > 0);
$ bin/clang -cc1 -triple i686-pc-win32 /tmp/a.cc -std=c++17 -emit-obj
error: cannot mangle this built-in __float128 type yet
/tmp/a.cc:9:32: error: invalid operands to binary expression ('StrictNumeric'
and 'int')
static_assert(StrictNumeric(1) > 0);
~~~~~~~~~~~~~~~~ ^ ~
2 errors generated.
Note that the source never mentions __float128, but Clang tries to use it when
it tries to find a conversion of the StrictNumeric that works with the >
expression. In the process, it instantiates is_floating_point_v<__float128>,
causing the mangling error.
Should BuiltinOperatorOverloadBuilder::addGenericBinaryArithmeticOverloads()
only consider types that are valid for the target?
(We hit this in Chromium with the latest MS SDK; see <a href="http://crbug.com/780311">http://crbug.com/780311</a>)</pre>
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