<html>
    <head>
      <base href="http://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 --- - Clang does not support ARMv6k"
   href="http://llvm.org/bugs/show_bug.cgi?id=21127">21127</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>Clang does not support ARMv6k
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>trunk
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>All
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>All
          </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>Driver
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>t.p.northover@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvmbugs@cs.uiuc.edu
          </td>
        </tr>

        <tr>
          <th>Classification</th>
          <td>Unclassified
          </td>
        </tr></table>
      <p>
        <div>
        <pre>E.g.

$ cat tmp.c
void foo() {
  asm volatile("wfe");
}
$ clang -target arm-linux-gnueabi -march=armv6k tmp.c -c
<inline asm>:1:2: error: instruction requires: armv6t2
        wfe

There are 2 problems here:

1. Clang treats "armv6k" the same as "armv6" for -march purposes (and defaults
to arm1136jf-s). It's actually a slight enhancement over stock v6, including
the WFE instruction in ARM mode. It should probably default to arm1176jzf-s,
since that's the first (and only) CPU guaranteed to have v6k but not others.

2. LLVM doesn't know about armv6k either. ARM1176JZF-S is treated as a plain
armv6 CPU by the backend and won't allow WFE to be assembled.</pre>
        </div>
      </p>
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