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<base href="https://bugs.llvm.org/">
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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [inline asm] Add -print-schedule scheduling comments to inline asm"
href="https://bugs.llvm.org/show_bug.cgi?id=35162">35162</a>
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<th>Summary</th>
<td>[inline asm] Add -print-schedule scheduling comments to inline asm
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<th>Product</th>
<td>new-bugs
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<th>Version</th>
<td>unspecified
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<th>Hardware</th>
<td>PC
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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>enhancement
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<th>Priority</th>
<td>P
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<th>Component</th>
<td>new bugs
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
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<th>Reporter</th>
<td>llvm-dev@redking.me.uk
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<th>CC</th>
<td>andrew.v.tischenko@gmail.com, craig.topper@gmail.com, gadi.haber@intel.com, llvm-bugs@lists.llvm.org, spatel+llvm@rotateright.com, zvi.rackover@intel.com
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<pre>As part of increasing scheduler model test coverage it would be very useful to
be get scheduling comments on ir instructions from inline asm:
define i64 @test_bsr64(i64 %a0, i64 *%a1) nounwind {
%1 = tail call i64 asm "bsr $1, $0", "=r,r"(i64 %a0) nounwind
%2 = tail call i64 asm "bsr $1, $0", "=r,*m"(i64 *%a1) nounwind
%3 = or i64 %1, %2
ret i64 %3
}
define i64 @test_bswap64(i64 %a0) nounwind {
%1 = tail call i64 asm "bswap $0", "=r,0"(i64 %a0) nounwind
ret i64 %1
}
Interestingly the bswap case succeeds but the bsr cases fail:
llc -mtriple=x86_64-unknown -mcpu=btver2 -print-schedule
test_bsr64: # @test_bsr64
# BB#0:
#APP
bsrq (%rsi), %rax
#NO_APP
#APP
bsrq %rdi, %rcx
#NO_APP
orq %rcx, %rax # sched: [1:0.50]
retq # sched: [4:1.00]
test_bswap64: # @test_bswap64
# BB#0:
bswapq %rdi # sched: [1:0.50]
movq %rdi, %rax # sched: [1:0.17]
retq # sched: [4:1.00]</pre>
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