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    <head>
      <base href="https://llvm.org/bugs/" />
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW --- - Integrated assembler rejects ldrexd/strexd in thumb mode"
   href="https://llvm.org/bugs/show_bug.cgi?id=31058">31058</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Integrated assembler rejects ldrexd/strexd in thumb mode
          </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>normal
          </td>
        </tr>

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

        <tr>
          <th>Component</th>
          <td>Frontend
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>sbc@chromium.org
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>These instructions are apparently valid in thumb2 mode but clang's integrated
asm rejects them:

void func() {
  int volatile *ptr;
  int ret;
  __asm__ __volatile__("ldrexd %0,[%1]\n"
      : "=&r" (ret)
      : "r" (ptr)
      : "cc", "memory"
      );
}


$ clang --target=arm-linux-gnueabihf -march=armv7-a -o test.o -c test.c 
-mthumb
test.c:4:24: error: instruction requires: arm-mode
  __asm__ __volatile__("ldrexd %0,[%1]\n"
                       ^
<inline asm>:1:2: note: instantiated into assembly here
        ldrexd r1,[r0]
        ^
1 error generated.

With -no-integrated-as the same code compiles fine:

See <a href="https://bugs.chromium.org/p/chromium/issues/detail?id=564059">https://bugs.chromium.org/p/chromium/issues/detail?id=564059</a></pre>
        </div>
      </p>
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