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<div class="moz-cite-prefix">On 07/11/2017 03:21 PM, Denys Zariaiev
via cfe-dev wrote:<br>
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cite="mid:CALVz_V8cx2wdhrVZ-q5wN5LYzA3VXOJi0_aBGZUH+xUCX5gokw@mail.gmail.com"
type="cite">
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<div dir="ltr">Hello,
<div><br>
</div>
<div>I'm curious, is it safe to change an alignment i128 type
for NVPTX target? I made a <a moz-do-not-send="true"
href="https://reviews.llvm.org/D34555">patch to the LLVM
backend</a> and added `-i128:128` into data layout.</div>
<div><br>
</div>
<div>But after it became that LLVM and Clang layouts are
different and error is thrown at Clang side:</div>
<div>> backend data layout
'e-i64:64-i128:128-v16:16-v32:32-n16:32:64' does not match
expected target description 'e-i64:64-v16:16-v32:32-n16:32:64'</div>
<div><br>
</div>
<div>Could you please help with advice, can I just make another
patch for Clang to modify the layout? Won't it break any
backward compatibility?</div>
</div>
</blockquote>
<br>
There could be some backward compatibility issues with linking new
IR files with old IR files (because you're increasing the alignment
requirements for i128), but often no more than other ISAs when new
SIMD instructions are added, etc. For the NVPTX backend, this might
be a concern if it affects anything in libdevice (the bitcode
library that is shipped with CUDA in bitcode form), otherwise, I
don't think it is a concern. In general, however, I think you should
just update Clang.<br>
<br>
-Hal<br>
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cite="mid:CALVz_V8cx2wdhrVZ-q5wN5LYzA3VXOJi0_aBGZUH+xUCX5gokw@mail.gmail.com"
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<div>Thanks a lot,</div>
<div>Denys Zariaiev</div>
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<pre class="moz-signature" cols="72">--
Hal Finkel
Lead, Compiler Technology and Programming Languages
Leadership Computing Facility
Argonne National Laboratory</pre>
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