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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Wrong tbaa metadata after load store vectorizer due to recent change"
href="https://bugs.llvm.org/show_bug.cgi?id=35225">35225</a>
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<th>Summary</th>
<td>Wrong tbaa metadata after load store vectorizer due to recent change
</td>
</tr>
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<th>Product</th>
<td>new-bugs
</td>
</tr>
<tr>
<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>new bugs
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
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<th>Reporter</th>
<td>mikael.holmen@ericsson.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
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<pre>Created <span class=""><a href="attachment.cgi?id=19377" name="attach_19377" title="reproducer">attachment 19377</a> <a href="attachment.cgi?id=19377&action=edit" title="reproducer">[details]</a></span>
reproducer
Reproduce with:
clang -mllvm -disable-llvm-optzns -S -emit-llvm -Xclang -O1 -pedantic tbaa.c -o
tbaa.ll
opt -O1 -load-store-vectorizer -S -o tbaa.opt.ll tbaa.ll
-debug-only=load-store-vectorizer
and then in the tbaa.opt.ll we see that the two stores have been merged to one:
store <2 x i32> %8, <2 x i32>* %9, align 4, !tbaa !6
but looking at !6 we see
!4 = !{!"omnipotent char", !5, i64 0}
!5 = !{!"Simple C/C++ TBAA"}
!6 = !{!7, !7, i64 0}
!7 = !{!"int", !4, i64 0}
so we say that the merged stores now write a single int?
This started happening recently, after the change r317311:
[Analysis] Refine matching and merging of TBAA tags
This patch combines the code that matches and merges TBAA access
tags. The aim is to simplify future changes and making sure that
these operations produce consistent results.
Differential Revision: <a href="https://reviews.llvm.org/D39463">https://reviews.llvm.org/D39463</a>
If reverting r317311 the merged store still get tbaa !6, but now !6 is:
!4 = !{!"omnipotent char", !5, i64 0}
!5 = !{!"Simple C/C++ TBAA"}
!6 = !{!4, !4, i64 0}</pre>
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