98a021fcbf
Prior to this patch, tail duplication handled debug info poorly - specifically, debug instructions would be dropped instead of being set undef, potentially extending the lifetimes of prior debug values that should be killed. The pass was also very aggressive with dropping debug info, dropping debug info even when the SSA value it referred to was still present. This patch attempts to handle debug info more carefully, checking to see whether each affected debug value can still be live, setting it undef if not. Reviewed By: jmorse Differential Revision: https://reviews.llvm.org/D106875
136 lines
5.4 KiB
YAML
136 lines
5.4 KiB
YAML
# RUN: llc -run-pass=early-tailduplication -mtriple=x86_64-unknown-linux-gnu %s -o - | FileCheck %s
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# Tail Duplication may update SSA values and invalidate any DBG_VALUEs that
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# use those values; those DBG_VALUEs should be set undef. This is tested
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# for DBG_VALUE users, and DBG_VALUE_LISTs that use the value multiple times.
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# CHECK: ![[VAR_J:[0-9]+]] = !DILocalVariable(name: "j"
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# CHECK: ![[VAR_K:[0-9]+]] = !DILocalVariable(name: "k"
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# CHECK-LABEL: bb.1.L:
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# CHECK: %[[REGISTER:[0-9]+]]:gr32 = PHI
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# CHECK-LABEL: bb.2.if.end4:
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# CHECK: DBG_VALUE_LIST ![[VAR_J]],
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# CHECK-SAME: %[[REGISTER]], 1, %[[REGISTER]]
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# CHECK: DBG_VALUE %[[REGISTER]], $noreg, ![[VAR_K]]
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--- |
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target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-linux-gnu"
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define dso_local void @main() local_unnamed_addr #0 !dbg !15 {
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entry:
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br label %L.outer
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L: ; preds = %L, %L.outer
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%tobool2.not = icmp eq i32 undef, 0
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br i1 %tobool2.not, label %if.end4, label %L
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if.end4: ; preds = %L
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call void @llvm.dbg.value(metadata !DIArgList(i32 %f.0.ph, i32 1, i32 %f.0.ph), metadata !19, metadata !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_LLVM_arg, 2, DW_OP_and, DW_OP_or, DW_OP_stack_value)), !dbg !21
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%cmp = icmp slt i32 %f.0.ph, undef
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br i1 %cmp, label %if.then5, label %if.end6
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if.then5: ; preds = %if.end4
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call void @h() #2
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br label %L.outer
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L.outer: ; preds = %if.then5, %entry
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%f.0.ph = phi i32 [ 0, %if.then5 ], [ 1, %entry ]
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br label %L
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if.end6: ; preds = %if.end4
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ret void
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}
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declare dso_local void @h() local_unnamed_addr
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declare void @llvm.dbg.value(metadata, metadata, metadata)
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!llvm.dbg.cu = !{!0}
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!llvm.module.flags = !{!13, !14}
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!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 13.0.0", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !3, splitDebugInlining: false, nameTableKind: None)
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!1 = !DIFile(filename: "tail-dup-debugvalue.c", directory: "/tmp")
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!2 = !{}
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!3 = !{!4, !7, !9, !11}
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!4 = !DIGlobalVariableExpression(var: !5, expr: !DIExpression())
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!5 = distinct !DIGlobalVariable(name: "a", scope: !0, file: !1, line: 2, type: !6, isLocal: false, isDefinition: true)
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!6 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!7 = !DIGlobalVariableExpression(var: !8, expr: !DIExpression())
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!8 = distinct !DIGlobalVariable(name: "b", scope: !0, file: !1, line: 2, type: !6, isLocal: false, isDefinition: true)
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!9 = !DIGlobalVariableExpression(var: !10, expr: !DIExpression())
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!10 = distinct !DIGlobalVariable(name: "c", scope: !0, file: !1, line: 2, type: !6, isLocal: false, isDefinition: true)
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!11 = !DIGlobalVariableExpression(var: !12, expr: !DIExpression())
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!12 = distinct !DIGlobalVariable(name: "d", scope: !0, file: !1, line: 2, type: !6, isLocal: false, isDefinition: true)
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!13 = !{i32 2, !"Debug Info Version", i32 3}
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!14 = !{i32 7, !"uwtable", i32 1}
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!15 = distinct !DISubprogram(name: "main", scope: !1, file: !1, line: 3, type: !16, scopeLine: 3, flags: DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !18)
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!16 = !DISubroutineType(types: !17)
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!17 = !{!6}
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!18 = !{!19, !20}
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!19 = !DILocalVariable(name: "j", scope: !15, file: !1, line: 14, type: !6)
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!20 = !DILocalVariable(name: "k", scope: !15, file: !1, line: 14, type: !6)
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!21 = !DILocation(line: 0, scope: !15)
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...
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---
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name: main
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alignment: 16
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tracksRegLiveness: true
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registers:
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- { id: 0, class: gr32 }
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- { id: 1, class: gr32 }
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- { id: 2, class: gr32 }
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- { id: 3, class: gr8 }
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- { id: 4, class: gr32 }
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- { id: 5, class: gr32 }
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- { id: 6, class: gr32 }
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frameInfo:
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maxAlignment: 1
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hasCalls: true
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machineFunctionInfo: {}
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body: |
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bb.0.entry:
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successors: %bb.4(0x80000000)
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%1:gr32 = MOV32ri 1
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JMP_1 %bb.4
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bb.1.L:
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successors: %bb.2(0x04000000), %bb.1(0x7c000000)
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%2:gr32 = MOV32r0 implicit-def dead $eflags
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%3:gr8 = COPY %2.sub_8bit
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TEST8rr %3, %3, implicit-def $eflags
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JCC_1 %bb.1, 5, implicit $eflags
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JMP_1 %bb.2
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bb.2.if.end4:
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successors: %bb.3(0x783e0f0f), %bb.5(0x07c1f0f1)
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DBG_VALUE_LIST !19, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_LLVM_arg, 2, DW_OP_and, DW_OP_or, DW_OP_stack_value), %0, 1, %0, debug-location !21
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DBG_VALUE %0, $noreg, !20, !DIExpression(), debug-location !21
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%5:gr32 = IMPLICIT_DEF
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%4:gr32 = SUB32rr %0, killed %5, implicit-def $eflags
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JCC_1 %bb.5, 13, implicit $eflags
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JMP_1 %bb.3
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bb.3.if.then5:
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successors: %bb.4(0x80000000)
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ADJCALLSTACKDOWN64 0, 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
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CALL64pcrel32 @h, csr_64, implicit $rsp, implicit $ssp, implicit-def $rsp, implicit-def $ssp
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ADJCALLSTACKUP64 0, 0, implicit-def dead $rsp, implicit-def dead $eflags, implicit-def dead $ssp, implicit $rsp, implicit $ssp
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%6:gr32 = MOV32r0 implicit-def dead $eflags
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bb.4.L.outer:
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successors: %bb.1(0x80000000)
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%0:gr32 = PHI %1, %bb.0, %6, %bb.3
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JMP_1 %bb.1
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bb.5.if.end6:
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RET 0
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...
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