5d9cd3b4ca
If a stack spill location is overwritten by another spill instruction, any variable locations pointing at that slot should be terminated. We cannot rely on spills always being restored to registers or variable locations being moved by a DBG_VALUE: the register allocator is entitled to spill a value and then forget about it when it goes out of liveness. To address this, scan for memory writes to spill locations, even those we don't consider to be normal "spills". isSpillInstruction and isLocationSpill distinguish the two now. After identifying spill overwrites, terminate the open range, and insert a $noreg DBG_VALUE for that variable. Differential Revision: https://reviews.llvm.org/D66941 llvm-svn: 371193
201 lines
11 KiB
YAML
201 lines
11 KiB
YAML
# RUN: llc -mtriple=x86_64-unknown-unknown %s -o - -run-pass=livedebugvalues | FileCheck %s
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#
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# Fix some of PR42772. Consider the code below: the arguments are forced onto
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# the stack by the FORCE_SPILL macro, and go out of liveness if the
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# "bees == 2" conditional is not taken. A spill slot is then re-used to
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# preserve quux over the second FORCE_SPILL, over-writing the value of either
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# "a" or "b". LiveDebugValues should detect when this happens, and terminate
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# stack-spill locations when they get overwritten by a new value.
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#
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# --------8<--------
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# #define FORCE_SPILL() \
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# __asm volatile("" : : : \
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# "rax", "rbx", "rcx", "rdx", "rsi", "rdi", "rbp", "r8", \
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# "r9", "r10", "r11", "r12", "r13", "r14", "r15")
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#
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# volatile int bees = 0;
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#
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# long int f(long int a, long int b) {
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# if (bees == 12)
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# return 3;
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#
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# FORCE_SPILL();
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# if (bees == 2)
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# return a - b;
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#
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# int quux = sum(1, 2);
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# FORCE_SPILL();
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# bees++;
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# return quux;
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# }
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# -------->8--------
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#
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# CHECK: ![[ANUM:[0-9]+]] = !DILocalVariable(name: "a"
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# CHECK: ![[BNUM:[0-9]+]] = !DILocalVariable(name: "b"
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#
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# These variables should be spilt,
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# CHECK-LABEL: bb.1.if.end:
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# CHECK: MOV64mr $rsp, 1, $noreg, 16, $noreg, killed renamable $rsi
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# CHECK-NEXT: DBG_VALUE $rsp, 0, ![[BNUM]], !DIExpression(
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# CHECK-NEXT: MOV64mr $rsp, 1, $noreg, 8, $noreg, killed renamable $rdi
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# CHECK-NEXT: DBG_VALUE $rsp, 0, ![[ANUM]], !DIExpression(
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# CHECK-NEXT: INLINEASM
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#
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# Then the location of "a" should be terminated when overwritten
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# CHECK-LABEL: bb.3.if.end3:
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# CHECK: CALL64pcrel32 @sum
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# CHECK-NEXT: MOV64mr $rsp, 1, $noreg, 8, $noreg, $rax
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# CHECK-NEXT: DBG_VALUE $noreg, $noreg, ![[ANUM]], !DIExpression()
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# CHECK-NEXT: INLINEASM
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--- |
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target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
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target triple = "x86_64-unknown-linux-gnu"
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@bees = external global i32, !dbg !0
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; Function Attrs: noinline norecurse nounwind readnone uwtable
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declare i64 @sum(i64, i64)
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; Function Attrs: noinline nounwind uwtable
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define i64 @f(i64 %a, i64 %b) !dbg !12 {
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entry:
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br label %if.end
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if.end:
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br label %if.then2
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if.then2:
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br label %if.end3
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if.end3:
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br label %return
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return:
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ret i64 0
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}
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!llvm.dbg.cu = !{!2}
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!llvm.module.flags = !{!8, !9, !10}
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!0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
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!1 = distinct !DIGlobalVariable(name: "bees", scope: !2, file: !3, line: 6, type: !6, isLocal: false, isDefinition: true)
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!2 = distinct !DICompileUnit(language: DW_LANG_C99, file: !3, producer: "clang", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5, nameTableKind: None)
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!3 = !DIFile(filename: "pr42772.c", directory: ".")
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!4 = !{}
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!5 = !{!0}
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!6 = !DIDerivedType(tag: DW_TAG_volatile_type, baseType: !7)
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!7 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
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!8 = !{i32 2, !"Dwarf Version", i32 4}
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!9 = !{i32 2, !"Debug Info Version", i32 3}
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!10 = !{i32 1, !"wchar_size", i32 4}
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!12 = distinct !DISubprogram(name: "f", scope: !3, file: !3, line: 15, type: !13, scopeLine: 15, flags: DIFlagPrototyped, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !2, retainedNodes: !16)
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!13 = !DISubroutineType(types: !14)
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!14 = !{!15, !15, !15}
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!15 = !DIBasicType(name: "long int", size: 64, encoding: DW_ATE_signed)
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!16 = !{!17, !18, !19}
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!17 = !DILocalVariable(name: "a", arg: 1, scope: !12, file: !3, line: 15, type: !15)
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!18 = !DILocalVariable(name: "b", arg: 2, scope: !12, file: !3, line: 15, type: !15)
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!19 = !DILocalVariable(name: "quux", scope: !12, file: !3, line: 23, type: !7)
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!28 = !DILocation(line: 1, column: 1, scope: !12)
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...
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---
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name: f
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tracksRegLiveness: true
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liveins:
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- { reg: '$rdi', virtual-reg: '' }
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- { reg: '$rsi', virtual-reg: '' }
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frameInfo:
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stackSize: 72
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offsetAdjustment: -72
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maxAlignment: 8
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adjustsStack: true
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hasCalls: true
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cvBytesOfCalleeSavedRegisters: 48
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fixedStack:
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- { id: 0, type: spill-slot, offset: -56, size: 8, alignment: 8, stack-id: default,
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callee-saved-register: '$rbx', callee-saved-restored: true, debug-info-variable: '',
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debug-info-expression: '', debug-info-location: '' }
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- { id: 1, type: spill-slot, offset: -48, size: 8, alignment: 16, stack-id: default,
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callee-saved-register: '$r12', callee-saved-restored: true, debug-info-variable: '',
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debug-info-expression: '', debug-info-location: '' }
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- { id: 2, type: spill-slot, offset: -40, size: 8, alignment: 8, stack-id: default,
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callee-saved-register: '$r13', callee-saved-restored: true, debug-info-variable: '',
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debug-info-expression: '', debug-info-location: '' }
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- { id: 3, type: spill-slot, offset: -32, size: 8, alignment: 16, stack-id: default,
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callee-saved-register: '$r14', callee-saved-restored: true, debug-info-variable: '',
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debug-info-expression: '', debug-info-location: '' }
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- { id: 4, type: spill-slot, offset: -24, size: 8, alignment: 8, stack-id: default,
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callee-saved-register: '$r15', callee-saved-restored: true, debug-info-variable: '',
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debug-info-expression: '', debug-info-location: '' }
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- { id: 5, type: spill-slot, offset: -16, size: 8, alignment: 16, stack-id: default,
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callee-saved-register: '$rbp', callee-saved-restored: true, debug-info-variable: '',
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debug-info-expression: '', debug-info-location: '' }
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stack:
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- { id: 0, name: '', type: spill-slot, offset: -72, size: 8, alignment: 8,
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stack-id: default, callee-saved-register: '', callee-saved-restored: true,
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debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
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- { id: 1, name: '', type: spill-slot, offset: -64, size: 8, alignment: 8,
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stack-id: default, callee-saved-register: '', callee-saved-restored: true,
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debug-info-variable: '', debug-info-expression: '', debug-info-location: '' }
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body: |
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bb.0.entry:
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successors: %bb.4, %bb.1
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liveins: $rdi, $rsi, $rbp, $r15, $r14, $r13, $r12, $rbx
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DBG_VALUE $rdi, $noreg, !17, !DIExpression(), debug-location !28
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DBG_VALUE $rdi, $noreg, !17, !DIExpression(), debug-location !28
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DBG_VALUE $rsi, $noreg, !18, !DIExpression(), debug-location !28
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DBG_VALUE $rsi, $noreg, !18, !DIExpression(), debug-location !28
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frame-setup PUSH64r killed $rbp, implicit-def $rsp, implicit $rsp, debug-location !28
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frame-setup PUSH64r killed $r15, implicit-def $rsp, implicit $rsp, debug-location !28
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frame-setup PUSH64r killed $r14, implicit-def $rsp, implicit $rsp, debug-location !28
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frame-setup PUSH64r killed $r13, implicit-def $rsp, implicit $rsp, debug-location !28
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frame-setup PUSH64r killed $r12, implicit-def $rsp, implicit $rsp, debug-location !28
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frame-setup PUSH64r killed $rbx, implicit-def $rsp, implicit $rsp, debug-location !28
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$rsp = frame-setup SUB64ri8 $rsp, 24, implicit-def dead $eflags
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renamable $ecx = MOV32rm $rip, 1, $noreg, @bees, $noreg, debug-location !28 :: (volatile dereferenceable load 4 from @bees)
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$eax = MOV32ri 3, implicit-def $rax
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CMP32ri8 killed renamable $ecx, 12, implicit-def $eflags, debug-location !28
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JCC_1 %bb.4, 4, implicit $eflags, debug-location !28
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bb.1.if.end:
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successors: %bb.2, %bb.3
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liveins: $rdi, $rsi
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MOV64mr $rsp, 1, $noreg, 16, $noreg, killed renamable $rsi :: (store 8 into %stack.1)
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MOV64mr $rsp, 1, $noreg, 8, $noreg, killed renamable $rdi :: (store 8 into %stack.0)
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INLINEASM &"", 1, 12, implicit-def dead early-clobber $rax, 12, implicit-def dead early-clobber $rbx, 12, implicit-def dead early-clobber $rcx, 12, implicit-def dead early-clobber $rdx, 12, implicit-def dead early-clobber $rsi, 12, implicit-def dead early-clobber $rdi, 12, implicit-def dead early-clobber $rbp, 12, implicit-def dead early-clobber $r8, 12, implicit-def dead early-clobber $r9, 12, implicit-def dead early-clobber $r10, 12, implicit-def dead early-clobber $r11, 12, implicit-def dead early-clobber $r12, 12, implicit-def dead early-clobber $r13, 12, implicit-def dead early-clobber $r14, 12, implicit-def dead early-clobber $r15, 12, implicit-def dead early-clobber $df, 12, implicit-def dead early-clobber $fpsw, 12, implicit-def dead early-clobber $eflags, debug-location !28
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renamable $eax = MOV32rm $rip, 1, $noreg, @bees, $noreg, debug-location !28 :: (volatile dereferenceable load 4 from @bees)
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CMP32ri8 killed renamable $eax, 2, implicit-def $eflags, debug-location !28
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JCC_1 %bb.3, 5, implicit killed $eflags, debug-location !28
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bb.2.if.then2:
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successors: %bb.4
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renamable $rax = MOV64rm $rsp, 1, $noreg, 8, $noreg :: (load 8 from %stack.0)
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renamable $rax = SUB64rm killed renamable $rax, $rsp, 1, $noreg, 16, $noreg, implicit-def dead $eflags, debug-location !28 :: (load 8 from %stack.1)
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JMP_1 %bb.4
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bb.3.if.end3:
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successors: %bb.4
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$edi = MOV32ri 1, implicit-def $rdi, debug-location !28
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$esi = MOV32ri 2, implicit-def $rsi, debug-location !28
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CALL64pcrel32 @sum, csr_64, implicit $rsp, implicit $ssp, implicit $rdi, implicit $rsi, implicit-def $rsp, implicit-def $ssp, implicit-def $rax, debug-location !28
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MOV64mr $rsp, 1, $noreg, 8, $noreg, $rax :: (store 8 into %stack.0)
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INLINEASM &"", 1, 12, implicit-def dead early-clobber $rax, 12, implicit-def dead early-clobber $rbx, 12, implicit-def dead early-clobber $rcx, 12, implicit-def dead early-clobber $rdx, 12, implicit-def dead early-clobber $rsi, 12, implicit-def dead early-clobber $rdi, 12, implicit-def dead early-clobber $rbp, 12, implicit-def dead early-clobber $r8, 12, implicit-def dead early-clobber $r9, 12, implicit-def dead early-clobber $r10, 12, implicit-def dead early-clobber $r11, 12, implicit-def dead early-clobber $r12, 12, implicit-def dead early-clobber $r13, 12, implicit-def dead early-clobber $r14, 12, implicit-def dead early-clobber $r15, 12, implicit-def dead early-clobber $df, 12, implicit-def dead early-clobber $fpsw, 12, implicit-def dead early-clobber $eflags, debug-location !28
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ADD32mi8 $rip, 1, $noreg, @bees, $noreg, 1, implicit-def dead $eflags, debug-location !28 :: (volatile store 4 into @bees), (volatile dereferenceable load 4 from @bees)
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renamable $rax = MOVSX64rm32 $rsp, 1, $noreg, 8, $noreg, debug-location !28 :: (load 4 from %stack.0, align 8)
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bb.4.return:
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liveins: $rax
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$rsp = frame-destroy ADD64ri8 $rsp, 24, implicit-def dead $eflags, debug-location !28
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$rbx = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !28
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$r12 = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !28
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$r13 = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !28
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$r14 = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !28
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$r15 = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !28
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$rbp = frame-destroy POP64r implicit-def $rsp, implicit $rsp, debug-location !28
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RETQ $rax, debug-location !28
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...
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