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<body><span class="vcard"><a class="email" href="mailto:howarth.mailing.lists@gmail.com" title="Jack Howarth <howarth.mailing.lists@gmail.com>"> <span class="fn">Jack Howarth</span></a>
</span> changed
<a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - non-deterministic stage2/stage3 file comparison failures in 3 stage bootstrap on x86_64 darwin and x86_64 linux"
href="http://bugs.llvm.org/show_bug.cgi?id=32342">bug 32342</a>
<br>
<table border="1" cellspacing="0" cellpadding="8">
<tr>
<th>What</th>
<th>Removed</th>
<th>Added</th>
</tr>
<tr>
<td style="text-align:right;">Resolution</td>
<td>---
</td>
<td>FIXED
</td>
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<td style="text-align:right;">Status</td>
<td>NEW
</td>
<td>RESOLVED
</td>
</tr></table>
<p>
<div>
<b><a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - non-deterministic stage2/stage3 file comparison failures in 3 stage bootstrap on x86_64 darwin and x86_64 linux"
href="http://bugs.llvm.org/show_bug.cgi?id=32342#c53">Comment # 53</a>
on <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - non-deterministic stage2/stage3 file comparison failures in 3 stage bootstrap on x86_64 darwin and x86_64 linux"
href="http://bugs.llvm.org/show_bug.cgi?id=32342">bug 32342</a>
from <span class="vcard"><a class="email" href="mailto:howarth.mailing.lists@gmail.com" title="Jack Howarth <howarth.mailing.lists@gmail.com>"> <span class="fn">Jack Howarth</span></a>
</span></b>
<pre>(In reply to Kyle Butt from <a href="show_bug.cgi?id=32342#c52">comment #52</a>)
<span class="quote">> With the help of an internal reproducer, I found the root cause. A fix is
> here: <a href="https://reviews.llvm.org/D31964">https://reviews.llvm.org/D31964</a> if someone would care to review.
>
> It's not the DenseMap, it is that we are not clearing ComputedEdges between
> functions. This causes spurious bad layout decisions when pointers end up
> colliding. It also leaks memory.</span >
Thanks. I can confirm that...
------------------------------------------------------------------------
r300022 | iteratee | 2017-04-11 23:18:20 -0400 (Tue, 11 Apr 2017) | 5 lines
CodeGen: BlockPlacement: Clear ComputedEdges between functions.
Not clearing was causing non-deterministic compiles for large files. Addresses
for MachineBasicBlocks would end up colliding and we would lay out a block that
we assumed had been pre-computed when it had not been.
------------------------------------------------------------------------
eliminated the non-determinism in the 3-stage bootstrap on
x86_64-apple-darwin16.</pre>
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