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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 - llc: ../lib/CodeGen/IfConversion.cpp:2056: [...] Assertion `(TailBB || !TrueBBI.IsBrAnalyzable) && "Unexpected!"' failed."
   href="https://bugs.llvm.org/show_bug.cgi?id=45302">45302</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>llc: ../lib/CodeGen/IfConversion.cpp:2056: [...] Assertion `(TailBB || !TrueBBI.IsBrAnalyzable) && "Unexpected!"' failed.
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>libraries
          </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>Common Code Generator Code
          </td>
        </tr>

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

        <tr>
          <th>Reporter</th>
          <td>mikael.holmen@ericsson.com
          </td>
        </tr>

        <tr>
          <th>CC</th>
          <td>llvm-bugs@lists.llvm.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=23278" name="attach_23278" title="bbi-40556_arm.mir reproducer.">attachment 23278</a> <a href="attachment.cgi?id=23278&action=edit" title="bbi-40556_arm.mir reproducer.">[details]</a></span>
bbi-40556_arm.mir reproducer.

Reproduce with:
 llc -mtriple=thumbv7-apple-ios -o /dev/null bbi-40556_arm.mir -run-pass
if-converter

which results in

llc: ../lib/CodeGen/IfConversion.cpp:2056: bool (anonymous
namespace)::IfConverter::IfConvertDiamond((anonymous
namespace)::IfConverter::BBInfo &, (anonymous
namespace)::IfConverter::IfcvtKind, unsigned int, unsigned int, bool, bool):
Assertion `(TailBB || !TrueBBI.IsBrAnalyzable) && "Unexpected!"' failed.

The reproducer is quite small:

--- |

  define void @func() minsize {
    ret void
  }

...
---
name:            func
body:             |
  bb.0:

    tBcc %bb.3, 1, $cpsr

  bb.1:

    tBcc %bb.2, 1, $cpsr
    tB %bb.2, 14, $noreg

  bb.2:

  bb.3:
  successors:
    tBX_RET 14, _
...

I assume the interesting part is the two branches from bb.1 to bb.2.

This started failing with 4f454b22754:
 [IfCvt][ARM] Optimise diamond if-conversion for code size

If revert that commit the crash goes away.</pre>
        </div>
      </p>


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