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<base href="https://llvm.org/bugs/" />
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<body><table border="1" cellspacing="0" cellpadding="8">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW --- - Post-RA scheduler moves code across asm sideeffect"
href="https://llvm.org/bugs/show_bug.cgi?id=28765">28765</a>
</td>
</tr>
<tr>
<th>Summary</th>
<td>Post-RA scheduler moves code across asm sideeffect
</td>
</tr>
<tr>
<th>Product</th>
<td>libraries
</td>
</tr>
<tr>
<th>Version</th>
<td>trunk
</td>
</tr>
<tr>
<th>Hardware</th>
<td>PC
</td>
</tr>
<tr>
<th>OS</th>
<td>All
</td>
</tr>
<tr>
<th>Status</th>
<td>NEW
</td>
</tr>
<tr>
<th>Severity</th>
<td>normal
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
<tr>
<th>Component</th>
<td>Common Code Generator Code
</td>
</tr>
<tr>
<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>Matthew.Arsenault@amd.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr>
<tr>
<th>Classification</th>
<td>Unclassified
</td>
</tr></table>
<p>
<div>
<pre>define void @loop(i32 addrspace(1)* %arg) nounwind {
bb:
br label %bb2
bb2:
%loop.idx = phi i32 [ 0, %bb ], [ %inc, %bb2 ]
call void asm sideeffect "
v_nop_e64
v_nop_e64", ""()
%inc = add nsw i32 %loop.idx, 1
%cmp = icmp slt i32 %inc, 10
br i1 %cmp, label %bb2, label %bb3 ; -
bb3:
ret void
}
llc -march=amdgcn on this testcase shows the add and compare are moved before
the inlineasm by the post-RA scheduler:
BB0_1: ; %bb2
; =>This Inner Loop Header: Depth=1
v_add_i32_e32 v0, vcc, 1, v0
v_cmp_gt_i32_e32 vcc, 10, v0
;;#ASMSTART
v_nop_e64
v_nop_e64
;;#ASMEND
s_and_b64 vcc, exec, vcc
s_cbranch_vccnz BB0_1</pre>
</div>
</p>
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