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<base href="http://llvm.org/bugs/" />
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - clang doesn't produce ARM EABI-compliant modulo runtime function"
href="http://llvm.org/bugs/show_bug.cgi?id=16387">16387</a>
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<th>Summary</th>
<td>clang doesn't produce ARM EABI-compliant modulo runtime function
</td>
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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>All
</td>
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<th>Status</th>
<td>NEW
</td>
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<th>Severity</th>
<td>normal
</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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<th>Reporter</th>
<td>kristof.beyls@arm.com
</td>
</tr>
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<th>CC</th>
<td>llvmbugs@cs.uiuc.edu
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<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>For the following program:
$ cat divmod.c
int f(int a, int b) {
int d = a/b;
int m = a%b;
int c = b%a;
return d+m+c;
}
compiled with the following command line:
clang -O3 -target armv7a-none-none-eabi -mcpu=cortex-a8 divmod.c -S
clang produces code that is not EABI compliant:
f:
push {r4, r5, r6, r11, lr}
add r11, sp, #12
sub sp, sp, #4
mov r5, r1
mov r4, r0
bl __aeabi_idiv
mov r6, r0
mov r0, r4
mov r1, r5
bl __modsi3
add r6, r0, r6
mov r0, r5
mov r1, r4
bl __modsi3
add r0, r6, r0
sub sp, r11, #12
pop {r4, r5, r6, r11, pc}
The problem is the calls to __modsi3. These are not compliant with the EABI.
Instead, clang should produce calls to __aeabi_idivmod or __aeabi_uidivmod for
modulo operations when producing EABI-compliant code.</pre>
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