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https://github.com/c64scene-ar/llvm-6502.git
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e4b44c1617
Per original comment, the intention of this loop is to go ahead and break the critical edge (in order to sink this instruction) if there's reason to believe doing so might "unblock" the sinking of additional instructions that define registers used by this one. The idea is that if we have a few instructions to sink "together" breaking the edge might be worthwhile. This commit makes a few small changes to help better realize this goal: First, modify the loop to ignore registers defined by this instruction. We don't sink definitions of physical registers, and sinking an SSA definition isn't going to unblock an upstream instruction. Second, ignore uses of physical registers. Instructions that define physical registers are rejected for sinking, and so moving this one won't enable moving any defining instructions. As an added bonus, while virtual register use-def chains are generally small due to SSA goodness, iteration over the uses and definitions (used by hasOneNonDBGUse) for physical registers like EFLAGS can be rather expensive in practice. (This is the original reason for looking at this) Finally, to keep things simple continue to only consider this trick for registers that have a single use (via hasOneNonDBGUse), but to avoid spuriously breaking critical edges only do so if the definition resides in the same MBB and therefore this one directly blocks it from being sunk as well. If sinking them together is meant to be, let the iterative nature of this pass sink the definition into this block first. Update tests to accomodate this change, add new testcase where sinking avoids pipeline stalls. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192608 91177308-0d34-0410-b5e6-96231b3b80d8
49 lines
2.7 KiB
LLVM
49 lines
2.7 KiB
LLVM
; RUN: llc < %s -mtriple=x86_64-apple-macosx -enable-misched \
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; RUN: -verify-machineinstrs | FileCheck %s
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;
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; Test LiveInterval update handling of DBG_VALUE.
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; rdar://12777252.
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;
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; CHECK: %entry
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; CHECK: DEBUG_VALUE: hg
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; CHECK: j
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%struct.node.0.27 = type { i16, double, [3 x double], i32, i32 }
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%struct.hgstruct.2.29 = type { %struct.bnode.1.28*, [3 x double], double, [3 x double] }
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%struct.bnode.1.28 = type { i16, double, [3 x double], i32, i32, [3 x double], [3 x double], [3 x double], double, %struct.bnode.1.28*, %struct.bnode.1.28* }
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declare void @llvm.dbg.declare(metadata, metadata) nounwind readnone
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define signext i16 @subdivp(%struct.node.0.27* nocapture %p, double %dsq, double %tolsq, %struct.hgstruct.2.29* nocapture byval align 8 %hg) nounwind uwtable readonly ssp {
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entry:
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call void @llvm.dbg.declare(metadata !{%struct.hgstruct.2.29* %hg}, metadata !4)
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%type = getelementptr inbounds %struct.node.0.27* %p, i64 0, i32 0
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%0 = load i16* %type, align 2
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%cmp = icmp eq i16 %0, 1
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br i1 %cmp, label %return, label %for.cond.preheader
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for.cond.preheader: ; preds = %entry
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%arrayidx6.1 = getelementptr inbounds %struct.hgstruct.2.29* %hg, i64 0, i32 1, i64 1
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%cmp22 = fcmp olt double 0.000000e+00, %dsq
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%conv24 = zext i1 %cmp22 to i16
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br label %return
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return: ; preds = %for.cond.preheader, %entry
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%retval.0 = phi i16 [ %conv24, %for.cond.preheader ], [ 0, %entry ]
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ret i16 %retval.0
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}
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declare void @llvm.dbg.value(metadata, i64, metadata) nounwind readnone
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!llvm.dbg.cu = !{!0}
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!0 = metadata !{i32 786449, metadata !11, i32 12, metadata !"clang version 3.3 (trunk 168918) (llvm/trunk 168920)", i1 true, metadata !"", i32 0, metadata !2, metadata !2, metadata !2, metadata !3, null, metadata !""} ; [ DW_TAG_compile_unit ] [MultiSource/Benchmarks/Olden/bh/newbh.c] [DW_LANG_C99]
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!1 = metadata !{metadata !2}
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!2 = metadata !{i32 0}
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!3 = metadata !{null}
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!4 = metadata !{i32 786689, null, metadata !"hg", metadata !5, i32 67109589, metadata !6, i32 0, i32 0} ; [ DW_TAG_arg_variable ] [hg] [line 725]
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!5 = metadata !{i32 786473, metadata !11} ; [ DW_TAG_file_type ]
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!6 = metadata !{i32 786454, metadata !11, null, metadata !"hgstruct", i32 492, i64 0, i64 0, i64 0, i32 0, metadata !7} ; [ DW_TAG_typedef ] [hgstruct] [line 492, size 0, align 0, offset 0] [from ]
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!7 = metadata !{i32 786451, metadata !11, null, metadata !"", i32 487, i64 512, i64 64, i32 0, i32 0, null, null, i32 0, null, i32 0, null} ; [ DW_TAG_structure_type ] [line 487, size 512, align 64, offset 0] [def] [from ]
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!11 = metadata !{metadata !"MultiSource/Benchmarks/Olden/bh/newbh.c", metadata !"MultiSource/Benchmarks/Olden/bh"}
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