[llvm] r215962 - [X86, X87 stackifier] Do not mark an operand of a debug instruction as kill.

Mon Aug 18 22:08:45 PDT 2014

On Mon, Aug 18, 2014 at 7:09 PM, Akira Hatanaka <ahatanaka at apple.com> wrote:
> Author: ahatanak
> Date: Mon Aug 18 21:09:57 2014
> New Revision: 215962
>
> URL: http://llvm.org/viewvc/llvm-project?rev=215962&view=rev
> Log:
> [X86, X87 stackifier] Do not mark an operand of a debug instruction as kill.
>
> <rdar://problem/16952634>
>
>
> Added:
>     llvm/trunk/test/CodeGen/X86/fpstack-debuginstr-kill.ll
> Modified:
>     llvm/trunk/lib/Target/X86/X86FloatingPoint.cpp
>
> Modified: llvm/trunk/lib/Target/X86/X86FloatingPoint.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86FloatingPoint.cpp?rev=215962&r1=215961&r2=215962&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86FloatingPoint.cpp (original)
> +++ llvm/trunk/lib/Target/X86/X86FloatingPoint.cpp Mon Aug 18 21:09:57 2014
> @@ -1654,6 +1654,9 @@ void FPS::setKillFlags(MachineBasicBlock
>
>    for (MachineBasicBlock::reverse_iterator I = MBB.rbegin(), E = MBB.rend();
>         I != E; ++I) {
> +    if (I->isDebugValue())
> +      continue;
> +
>      BitVector Defs(8);
>      SmallVector<MachineOperand *, 2> Uses;
>      MachineInstr &MI = *I;
>
> Added: llvm/trunk/test/CodeGen/X86/fpstack-debuginstr-kill.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/fpstack-debuginstr-kill.ll?rev=215962&view=auto
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/fpstack-debuginstr-kill.ll (added)
> +++ llvm/trunk/test/CodeGen/X86/fpstack-debuginstr-kill.ll Mon Aug 18 21:09:57 2014
> @@ -0,0 +1,71 @@
> +; RUN: llc < %s -mcpu=generic -mtriple=i386-apple-darwin -no-integrated-as

Generally we've made a habit of checking in the user-level source
along with the IR for debug info tests, to make them easier to
maintain in the future, should the schema change greatly, etc. But I
realize this is swift code (guessing by the 'sw' prefix in the label
names) & with the swift compiler not being part of the LLVM project (&
still changing a lot) adding swift code here's probably not much help.

At least a bit more detailed documentation about which part of all of
this code is relevant might be helpful?

Could the code be simplified (generally we try to simplify the
input/source code, rather than hand-simplify the IR, in these debug
info tests - but since there's no source, the IR  could be
hand-simplified (but I'd suggest trying to simplify the input source
as much as possible first - since that'll also simplify the metadata,
too)). Perhaps there's a C++ reproduction you could use, in which case
we wouldn't have to worry about the swiftyness of the code and it
might be more obvious?

Is this test just checking we don't crash? (I don't see any FileCheck,
etc) "does not crash" isn't a great thing to test for. There must've
been some behavior that was expected of this code other than "does not
crash" - perhaps we could/should test for that behavior?

> +
> + at g1 = global double 0.000000e+00, align 8
> + at g2 = global i32 0, align 4
> +
> +define void @_Z16fpuop_arithmeticjj(i32, i32) {
> +entry:
> +  switch i32 undef, label %sw.bb.i1921 [
> +  ]
> +
> +sw.bb261:                                         ; preds = %entry, %entry
> +  unreachable
> +
> +sw.bb.i1921:                                      ; preds = %if.end504
> +  switch i32 undef, label %if.end511 [
> +    i32 1, label %sw.bb27.i
> +  ]
> +
> +sw.bb27.i:                                        ; preds = %sw.bb.i1921
> +  %conv.i.i1923 = fpext float undef to x86_fp80
> +  br label %if.end511
> +
> +if.end511:                                        ; preds = %sw.bb27.i, %sw.bb13.i
> +  %src.sroa.0.0.src.sroa.0.0.2280 = phi x86_fp80 [ %conv.i.i1923, %sw.bb27.i ], [ undef, %sw.bb.i1921 ]
> +  switch i32 undef, label %sw.bb992 [
> +    i32 3, label %sw.bb735
> +    i32 18, label %if.end41.i2210
> +  ]
> +
> +sw.bb735:                                         ; preds = %if.end511
> +  %2 = call x86_fp80 asm sideeffect "frndint", "={st},0,~{dirflag},~{fpsr},~{flags}"(x86_fp80 %src.sroa.0.0.src.sroa.0.0.2280)
> +  unreachable
> +
> +if.end41.i2210:                                   ; preds = %if.end511
> +  call void @llvm.dbg.value(metadata !{x86_fp80 %src.sroa.0.0.src.sroa.0.0.2280}, i64 0, metadata !20)
> +  unreachable
> +
> +sw.bb992:                                         ; preds = %if.end511
> +  ret void
> +}
> +
> +declare void @llvm.dbg.value(metadata, i64, metadata)
> +
> +!llvm.dbg.cu = !{!0}
> +!llvm.module.flags = !{!24, !25}
> +!0 = metadata !{i32 786449, metadata !1, i32 4, metadata !"clang version 3.6.0 (http://llvm.org/git/clang 8444ae7cfeaefae031f8fedf0d1435ca3b14d90b) (http://llvm.org/git/llvm 886f0101a7d176543b831f5efb74c03427244a55)", i1 true, metadata !"", i32 0, metadata !2, metadata !2, metadata !3, metadata !21, metadata !2, metadata !"", i32 1} ; [ DW_TAG_compile_unit ] [x87stackifier/fpu_ieee.cpp] [DW_LANG_C_plus_plus]
> +!1 = metadata !{metadata !"fpu_ieee.cpp", metadata !"x87stackifier"}
> +!2 = metadata !{}
> +!3 = metadata !{metadata !4}
> +!4 = metadata !{i32 786478, metadata !5, metadata !6, metadata !"fpuop_arithmetic", metadata !"fpuop_arithmetic", metadata !"_Z16fpuop_arithmeticjj", i32 11, metadata !7, i1 false, i1 true, i32 0, i32 0, null, i32 256, i1 true, void (i32, i32)* @_Z16fpuop_arithmeticjj, null, null, metadata !10, i32 13} ; [ DW_TAG_subprogram ] [line 11] [def] [scope 13] [fpuop_arithmetic]
> +!5 = metadata !{metadata !"f1.cpp", metadata !"x87stackifier"}
> +!6 = metadata !{i32 786473, metadata !5}          ; [ DW_TAG_file_type ] [x87stackifier/f1.cpp]
> +!7 = metadata !{i32 786453, i32 0, null, metadata !"", i32 0, i64 0, i64 0, i64 0, i32 0, null, metadata !8, i32 0, null, null, null} ; [ DW_TAG_subroutine_type ] [line 0, size 0, align 0, offset 0] [from ]
> +!8 = metadata !{null, metadata !9, metadata !9}
> +!9 = metadata !{i32 786468, null, null, metadata !"unsigned int", i32 0, i64 32, i64 32, i64 0, i32 0, i32 7} ; [ DW_TAG_base_type ] [unsigned int] [line 0, size 32, align 32, offset 0, enc DW_ATE_unsigned]
> +!10 = metadata !{metadata !11, metadata !12, metadata !13, metadata !18, metadata !20}
> +!11 = metadata !{i32 786689, metadata !4, metadata !"", metadata !6, i32 16777227, metadata !9, i32 0, i32 0} ; [ DW_TAG_arg_variable ] [line 11]
> +!12 = metadata !{i32 786689, metadata !4, metadata !"", metadata !6, i32 33554443, metadata !9, i32 0, i32 0} ; [ DW_TAG_arg_variable ] [line 11]
> +!13 = metadata !{i32 786688, metadata !4, metadata !"x", metadata !6, i32 14, metadata !14, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [x] [line 14]
> +!14 = metadata !{i32 786454, metadata !5, null, metadata !"fpu_extended", i32 3, i64 0, i64 0, i64 0, i32 0, metadata !15} ; [ DW_TAG_typedef ] [fpu_extended] [line 3, size 0, align 0, offset 0] [from fpu_register]
> +!15 = metadata !{i32 786454, metadata !5, null, metadata !"fpu_register", i32 2, i64 0, i64 0, i64 0, i32 0, metadata !16} ; [ DW_TAG_typedef ] [fpu_register] [line 2, size 0, align 0, offset 0] [from uae_f64]
> +!16 = metadata !{i32 786454, metadata !5, null, metadata !"uae_f64", i32 1, i64 0, i64 0, i64 0, i32 0, metadata !17} ; [ DW_TAG_typedef ] [uae_f64] [line 1, size 0, align 0, offset 0] [from double]
> +!17 = metadata !{i32 786468, null, null, metadata !"double", i32 0, i64 64, i64 64, i64 0, i32 0, i32 4} ; [ DW_TAG_base_type ] [double] [line 0, size 64, align 64, offset 0, enc DW_ATE_float]
> +!18 = metadata !{i32 786688, metadata !4, metadata !"a", metadata !6, i32 15, metadata !19, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [a] [line 15]
> +!19 = metadata !{i32 786468, null, null, metadata !"int", i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
> +!20 = metadata !{i32 786688, metadata !4, metadata !"value", metadata !6, i32 16, metadata !14, i32 0, i32 0} ; [ DW_TAG_auto_variable ] [value] [line 16]
> +!21 = metadata !{metadata !22, metadata !23}
> +!22 = metadata !{i32 786484, i32 0, null, metadata !"g1", metadata !"g1", metadata !"", metadata !6, i32 5, metadata !14, i32 0, i32 1, double* @g1, null} ; [ DW_TAG_variable ] [g1] [line 5] [def]
> +!23 = metadata !{i32 786484, i32 0, null, metadata !"g2", metadata !"g2", metadata !"", metadata !6, i32 6, metadata !19, i32 0, i32 1, i32* @g2, null} ; [ DW_TAG_variable ] [g2] [line 6] [def]
> +!24 = metadata !{i32 2, metadata !"Dwarf Version", i32 2}
> +!25 = metadata !{i32 2, metadata !"Debug Info Version", i32 1}
>
>
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