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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 - Crash with __builtin_memcpy_inline when source is an array"
href="https://bugs.llvm.org/show_bug.cgi?id=48294">48294</a>
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<th>Summary</th>
<td>Crash with __builtin_memcpy_inline when source is an array
</td>
</tr>
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<th>Product</th>
<td>clang
</td>
</tr>
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<th>Version</th>
<td>11.0
</td>
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<tr>
<th>Hardware</th>
<td>PC
</td>
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<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>
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<th>Component</th>
<td>Frontend
</td>
</tr>
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<th>Assignee</th>
<td>unassignedclangbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>jasper.mattsson@gmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
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<pre>Created <span class=""><a href="attachment.cgi?id=24208" name="attach_24208" title="Full backtrace from crash">attachment 24208</a> <a href="attachment.cgi?id=24208&action=edit" title="Full backtrace from crash">[details]</a></span>
Full backtrace from crash
__builtin_memcpy_inline uses custom type checking, and thus does not perform
default argument conversions. Basically, I invoked the builtin with a pointer
and an array as its arguments, expecting array-to-pointer decay to happen.
Instead, Clang crashed as codegen.
I'm not sure if default conversions should happen with __builtin_memcpy_inline,
but it probably should not crash.
Example code:
int main() {
char to, from[1];
__builtin_memcpy_inline(&to, from, 1);
}
Snippet from backtrace:
#4 0x00007f5c1668a2b3
clang::CodeGen::CodeGenModule::getNaturalTypeAlignment(clang::QualType,
clang::CodeGen::LValueBaseInfo*, clang::CodeGen::TBAAAccessInfo*, bool)
(/usr/bin/../lib/libclang-cpp.so.11+0x1bd82b3)
#5 0x00007f5c1648cc42
clang::CodeGen::CodeGenFunction::EmitPointerWithAlignment(clang::Expr const*,
clang::CodeGen::LValueBaseInfo*, clang::CodeGen::TBAAAccessInfo*)
(/usr/bin/../lib/libclang-cpp.so.11+0x19dac42)
#6 0x00007f5c163cca99
clang::CodeGen::CodeGenFunction::EmitBuiltinExpr(clang::GlobalDecl, unsigned
int, clang::CallExpr const*, clang::CodeGen::ReturnValueSlot)
(/usr/bin/../lib/libclang-cpp.so.11+0x191aa99)
#7 0x00007f5c1649379e
clang::CodeGen::CodeGenFunction::EmitCallExpr(clang::CallExpr const*,
clang::CodeGen::ReturnValueSlot) (/usr/bin/../lib/libclang-cpp.so.11+0x19e179e)</pre>
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