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    <head>
      <base href="https://bugs.llvm.org/">
    </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 - builtin_assume_aligned uses 32-bits for alignment"
   href="https://bugs.llvm.org/show_bug.cgi?id=43638">43638</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>builtin_assume_aligned uses 32-bits for alignment
          </td>
        </tr>

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

        <tr>
          <th>Version</th>
          <td>unspecified
          </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>LLVM Codegen
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>joel.gouly@gmail.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org, neeilans@live.com, richard-llvm@metafoo.co.uk
          </td>
        </tr></table>
      <p>
        <div>
        <pre>This test cases crashes clang, because 'unsigned' is used for the alignment,
rather than 'size_t'.

    const void * square(const void* num) {
      void* a = __builtin_assume_aligned((const void*)num, 4294967296);
      return a;
    }

Assertion:

llvm/llvm/include/llvm/IR/IRBuilder.h:2624: llvm::CallInst* llvm::IRBuilder<T,
Inserter>::CreateAlignmentAssumption(const llvm::DataLayout&, llvm::Value*,
unsigned int, llvm::Value*, llvm::Value**) [with T = llvm::ConstantFolder;
Inserter = clang::CodeGen::CGBuilderInserter]: Assertion `Alignment != 0 &&
"Invalid Alignment"' failed.

The affected functions are `EmitAlignmentAssumption` in
lib/CodeGen/CodeGenFunction.h and also `CreateAlignmentAssumption` in
include/llvm/IR/IRBuilder.h</pre>
        </div>
      </p>


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