<html>
    <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 - [Win][AArch64] Miscompilation in rel-lookup-table-converter-pass"
   href="https://bugs.llvm.org/show_bug.cgi?id=50227">50227</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>[Win][AArch64] Miscompilation in rel-lookup-table-converter-pass
          </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>Windows NT
          </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>Richard.Townsend@arm.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>The rel-lookup-table-converter-pass seems to be causing crashing bugs on
Windows on Arm, starting from this commit:

<a href="https://github.com/llvm/llvm-project/commit/57b259a852a6383880f5d0875d848420bb3c2945">https://github.com/llvm/llvm-project/commit/57b259a852a6383880f5d0875d848420bb3c2945</a> 

This is causing crashes for the electron project [1], also see discussion in
Chromium [2]

[1] <a href="https://github.com/electron/electron/issues/28876">https://github.com/electron/electron/issues/28876</a>
[2] <a href="https://bugs.chromium.org/p/chromium/issues/detail?id=1204788">https://bugs.chromium.org/p/chromium/issues/detail?id=1204788</a>

blink_unittests.exe!blink::GetNonAliasPropertyInternal(blink::CSSPropertyID id)
Line 2968       C++

Without the new pass:
00007FF7A33F2DFC D00171C9             adrp        x9,string
"gen/third_party/blink/renderer/c"...+20h (07FF7A622C000h)  
00007FF7A33F2E00 51000A68             sub         w8,w19,#2  
00007FF7A33F2E04 91014129             add         x9,x9,#0x50  
00007FF7A33F2E08 B8A8D928             ldrsw       x8,[x9,w8 sxtw #2]  
00007FF7A33F2E0C F9400FE0             ldr         x0,[sp,#0x18]  
00007FF7A33F2E10 8B080133             add         x19,x9,x8  
00007FF7A33F2E14 941717EB             bl          __security_check_cookie
(07FF7A39B8DC0h)  

Without:
00007FF71C8B324C B00171C8             adrp        x8,string "const char
*__cdecl WTF::GetStri"...+10h (07FF71F6EC000h)  
00007FF71C8B3250 91040108             add         x8,x8,#0x100  
00007FF71C8B3254 8B33CD08             add         x8,x8,w19,sxtw #3  
00007FF71C8B3258 F9400FE0             ldr         x0,[sp,#0x18]  
00007FF71C8B325C F85F0113             ldur        x19,[x8,#-0x10]  
00007FF71C8B3260 94171808             bl          __security_check_cookie
(07FF71CE79280h)  

(Reproducer will be uploaded shortly).</pre>
        </div>
      </p>


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