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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [AMDGPU][MC][GFX8][GFX9] Incorrect dst/data size for MIMG opcodes with d16 modifier"
href="https://bugs.llvm.org/show_bug.cgi?id=36154">36154</a>
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<th>Summary</th>
<td>[AMDGPU][MC][GFX8][GFX9] Incorrect dst/data size for MIMG opcodes with d16 modifier
</td>
</tr>
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<th>Product</th>
<td>libraries
</td>
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<th>Version</th>
<td>trunk
</td>
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<th>Hardware</th>
<td>PC
</td>
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<th>OS</th>
<td>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>enhancement
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Backend: AMDGPU
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>dpreobrazhensky@luxoft.com
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org
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<p>
<div>
<pre>Currently assembler assumes that MIMG VGPR data size (in dwords) may be
computed as follows:
count_population(dmask) + tfe
However it turned out that d16 affects MIMG data size as well. This is not
described in the spec.
Specifically,
- for GFX8.0, d16 means that data in VGPRs are stored unpacked. Each 16-bit
value occupies one VGPR. The formula shown above holds true.
- for GFX8.1 and GFX9, d16 means that data are stored packed. VGPR data size
(in dwords) shall be computed as follows:
(count_population(dmask) + 1) / 2 + tfe
SP3 assembler does not seem to account for this difference.
NB: this change in d16 behavior affects both assembler and disassembler.</pre>
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