<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/63525>63525</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Under the O2 optimization level, compiler_rt has an error about instcombine optimization
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          zhusihang
      </td>
    </tr>
</table>

<pre>
    When compiling compiler-rt/lib/profile/InstrProfilingMerge.c:125:20, bad instruction folding by foldGEPICmp during instcombine.
```
 origin instruction:
  %cmp = icmp ult ptr %add.ptr6, %add.ptr4, !dbg !153
  new instruction after foldGEPICmp:
  <badref> = icmp slt i64 %mul, 0
 which corresponds to code or function is:
  if (SrcNameStart < SrcCountersStart)
 ^
```
Unsigned comparison (aka. SrcName Start < Src Counter Start) becomes signed comparison (aka. Header->CountersSize * __llvm_profile_counter_entry_size() < 0). 
The original overflow judgment becomes a comparison of the second parameter of the gep instruction with 0. The result is always false, causing the corresponding overflow judgment semantics to fail.
</pre>
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