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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - SelectDAGISel::SelectAllBasicBlocks fails to legalize instructions"
href="http://llvm.org/bugs/show_bug.cgi?id=16717">16717</a>
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<th>Summary</th>
<td>SelectDAGISel::SelectAllBasicBlocks fails to legalize instructions
</td>
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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>Windows NT
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>normal
</td>
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>Common Code Generator Code
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>manjian2006@gmail.com
</td>
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<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
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<th>Classification</th>
<td>Unclassified
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<div>
<pre>Created <span class=""><a href="attachment.cgi?id=10938" name="attach_10938" title="source that llvm generates wrong code">attachment 10938</a> <a href="attachment.cgi?id=10938&action=edit" title="source that llvm generates wrong code">[details]</a></span>
source that llvm generates wrong code
compiling option:
-O0 -fPIC -target armv5te-linux-androideabi -S 1.cpp
That generates code which does pic incorrectly:
__cxx_global_var_init:
push {r11, lr}
mov r11, sp
sub sp, sp, #8
ldr r0, .LCPI0_1
=> ldr r1, .LCPI0_0
ldr r0, [r1, r0]
bl _ZN1HC1Ev
...
.LCPI0_0:
.long g_h(GOT)
.LCPI0_1:
.long _GLOBAL_OFFSET_TABLE_
The marked code apparently missing add r0,pc
And I have found -O2 generates code correctly.After examining the code
SelectDAGISel::SelectAllBasicBlocks,I can see FastIS is activated in O0 but not
in O2,and that consume all the changes to do SelectBasicBlock.That will leave
no meaningful data to legalize the code(SDB is empty).
I guess FastIS->SelectInstruction may not do its job well.</pre>
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