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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Inline asm validation doesn't use delayed warnings"
href="https://bugs.llvm.org/show_bug.cgi?id=41027">41027</a>
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<th>Summary</th>
<td>Inline asm validation doesn't use delayed warnings
</td>
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<th>Product</th>
<td>clang
</td>
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<th>Version</th>
<td>unspecified
</td>
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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>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Frontend
</td>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
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<th>Reporter</th>
<td>joerg@NetBSD.org
</td>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
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<p>
<div>
<pre>Consider the following test case:
static inline void outl(unsigned port, unsigned data) {
if (__builtin_constant_p(port) && port < 0x100) {
__asm volatile("outl %0,%w1" : : "a"(data), "n"(port));
} else {
__asm volatile("outl %0,%w1" : : "a"(data), "d"(port));
}
}
void f(unsigned port) { outl(1, 1); }
This kind of assembler construct has been used for ages on various
architectures, especially if there are instruction forms that require
hard-coded immediates. Variants with __always_inline__ apply as well. This got
broken by the recent validation for 'n' as it doesn't use the dead code warning
elimination support.</pre>
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