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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [MC][Thumb2] .w suffix rejected for certain ldr and str operands"
href="https://bugs.llvm.org/show_bug.cgi?id=50664">50664</a>
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<th>Summary</th>
<td>[MC][Thumb2] .w suffix rejected for certain ldr and str operands
</td>
</tr>
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<th>Product</th>
<td>libraries
</td>
</tr>
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<th>Version</th>
<td>trunk
</td>
</tr>
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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>
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<th>Priority</th>
<td>P
</td>
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<th>Component</th>
<td>Backend: ARM
</td>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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</tr>
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<th>Reporter</th>
<td>rprichard@google.com
</td>
</tr>
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<th>CC</th>
<td>llvm-bugs@lists.llvm.org, smithp352@googlemail.com, Ties.Stuij@arm.com
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<p>
<div>
<pre>LLVM can assemble this Thumb2 code (clang --target=armv7a-linux-gnueabi):
.syntax unified
.thumb
ldr.w r0, [r1, #0xf00]
But not this:
.syntax unified
.thumb
ldr.w r0, [r1, #-2]
test.S:3:15: error: invalid operand for instruction
ldr.w r0, [r1, #-2]
^
It will assemble if I remove the ".w" suffix. The disassembly is then:
00000000 <.text>:
0: f851 0c02 ldr.w r0, [r1, #-2]
... which indicates a wide instruction.
Maybe the fix for <a class="bz_bug_link
bz_status_RESOLVED bz_closed"
title="RESOLVED FIXED - [Integrated Assembler][Thumb2] ldr and str missing .w suffix aliases"
href="show_bug.cgi?id=49118">bug #49118</a> was incomplete?
There are some similar instructions that, IIRC, use the same encoding, and have
the same problem. They're wide instructions that can only be assembled if the
".w" suffix is omitted:
ldr.w r0, [r1, #2]!
ldr.w r0, [r1], #2
ldr.w r0, [r1, #-0]</pre>
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