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      <base href="https://bugs.llvm.org/">
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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 - compound assignment invalid operands"
   href="https://bugs.llvm.org/show_bug.cgi?id=42782">42782</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>compound assignment invalid operands
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>clang
          </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>enhancement
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>P
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>-New Bugs
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>unassignedclangbugs@nondot.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>jaopaulolc@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>htmldeveloper@gmail.com, llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=22295" name="attach_22295" title="stack dump">attachment 22295</a> <a href="attachment.cgi?id=22295&action=edit" title="stack dump">[details]</a></span>
stack dump

The code I am attaching has 2 compound assignments where variable x is the LHS,
respectively, line 6 and 8.

The assignment on line 6 works fine. However line 8's assignment triggers the
following error:

atomic.c:8:5: error: invalid operands to binary expression ('_Atomic(int)' and
'_Atomic(int)')

The problem seems to be the fact that only the LHS' _Atomic type-specifier is
ignored here:

<a href="https://github.com/llvm/llvm-project/blob/736e8aa8ed48fd8c29a909bf616965d0f8677bca/clang/lib/Sema/SemaExpr.cpp#L1358">https://github.com/llvm/llvm-project/blob/736e8aa8ed48fd8c29a909bf616965d0f8677bca/clang/lib/Sema/SemaExpr.cpp#L1358</a>

Which makes LHSType and RHSType different and triggers the error message here:

<a href="https://github.com/llvm/llvm-project/blob/736e8aa8ed48fd8c29a909bf616965d0f8677bca/clang/lib/Sema/SemaExpr.cpp#L9462">https://github.com/llvm/llvm-project/blob/736e8aa8ed48fd8c29a909bf616965d0f8677bca/clang/lib/Sema/SemaExpr.cpp#L9462</a>

I tried to "fix" this by adding the following right after SemaExpr.cpp#L1358:

if (const AtomicType *AtomicRHS = RHSType->getAs<AtomicType>())
  RHSType = AtomicRHS->getValueType();

However this breaks the CodeGen at ScalarExprEmitter::EmitCompoundAssignLValue.
(please find all resources attached).</pre>
        </div>
      </p>


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