Skip to content

[DebugInfo][LICM] Salvage dbg_values for the dead instructions to erase #138796

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
May 12, 2025
Merged

[DebugInfo][LICM] Salvage dbg_values for the dead instructions to erase #138796

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
23a593a
[debuginfo] fix #138684: salvage dbg_values for dead instructions in …
Apochens May 7, 2025
15c8fb9
nit
Apochens May 9, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
15 changes: 12 additions & 3 deletions llvm/lib/Transforms/Scalar/LICM.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2538,6 +2538,7 @@ static bool hoistGEP(Instruction &I, Loop &L, ICFLoopSafetyInfo &SafetyInfo,
IsInBounds);
GEP->replaceAllUsesWith(NewGEP);
eraseInstruction(*GEP, SafetyInfo, MSSAU);
salvageDebugInfo(*Src);
eraseInstruction(*Src, SafetyInfo, MSSAU);
return true;
}
Expand Down Expand Up @@ -2592,7 +2593,10 @@ static bool hoistAdd(ICmpInst::Predicate Pred, Value *VariantLHS,
ICmp.setPredicate(Pred);
ICmp.setOperand(0, VariantOp);
ICmp.setOperand(1, NewCmpOp);
eraseInstruction(cast<Instruction>(*VariantLHS), SafetyInfo, MSSAU);

Instruction &DeadI = cast<Instruction>(*VariantLHS);
salvageDebugInfo(DeadI);
eraseInstruction(DeadI, SafetyInfo, MSSAU);
return true;
}

Expand Down Expand Up @@ -2670,7 +2674,10 @@ static bool hoistSub(ICmpInst::Predicate Pred, Value *VariantLHS,
ICmp.setPredicate(Pred);
ICmp.setOperand(0, VariantOp);
ICmp.setOperand(1, NewCmpOp);
eraseInstruction(cast<Instruction>(*VariantLHS), SafetyInfo, MSSAU);

Instruction &DeadI = cast<Instruction>(*VariantLHS);
salvageDebugInfo(DeadI);
eraseInstruction(DeadI, SafetyInfo, MSSAU);
return true;
}

Expand Down Expand Up @@ -2877,8 +2884,10 @@ static bool hoistBOAssociation(Instruction &I, Loop &L,

// (LV op C1) might not be erased if it has more uses than the one we just
// replaced.
if (BO0->use_empty())
if (BO0->use_empty()) {
salvageDebugInfo(*BO0);
eraseInstruction(*BO0, SafetyInfo, MSSAU);
}

return true;
}
Expand Down
70 changes: 70 additions & 0 deletions llvm/test/Transforms/LICM/salvage-hoisted-add.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,70 @@
; RUN: opt -S -passes=licm %s | FileCheck %s

; Check that hoistAdd() in LICM salvages the dbg_value for the hoisted add
; instruction.

define i32 @hoist_add(ptr %p, ptr %x_p, ptr %length_p) !dbg !5 {
; CHECK-LABEL: define i32 @hoist_add(
; CHECK-LABEL: loop:
; CHECK: #dbg_value(!DIArgList(i32 [[X:%.*]], i32 [[IV:%.*]]), [[META9:![0-9]+]], !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_plus, DW_OP_stack_value), [[META16:![0-9]+]])
;
entry:
%x = load i32, ptr %x_p, align 4, !dbg !20, !range !21
%length = load i32, ptr %length_p, align 4, !dbg !22, !range !21
br label %loop, !dbg !23

loop: ; preds = %backedge, %entry
%iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ], !dbg !24
%arith = add nsw i32 %x, %iv, !dbg !25
#dbg_value(i32 %arith, !13, !DIExpression(), !25)
%x_check = icmp slt i32 %arith, 4, !dbg !26
br i1 %x_check, label %out_of_bounds, label %backedge, !dbg !27

backedge: ; preds = %loop
%el.ptr = getelementptr i32, ptr %p, i32 %iv, !dbg !28
store i32 1, ptr %el.ptr, align 4, !dbg !29
%iv.next = add nuw nsw i32 %iv, 4, !dbg !30
%loop_cond = icmp slt i32 %iv.next, %length, !dbg !31
br i1 %loop_cond, label %loop, label %exit, !dbg !32

exit: ; preds = %backedge
ret i32 %iv.next, !dbg !33

out_of_bounds: ; preds = %loop
ret i32 -1, !dbg !34
}

!llvm.dbg.cu = !{!0}
!llvm.debugify = !{!2, !3}
!llvm.module.flags = !{!4}

!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
!1 = !DIFile(filename: "salvage-hoisted-add", directory: "/")
!2 = !{i32 14}
!3 = !{i32 8}
!4 = !{i32 2, !"Debug Info Version", i32 3}
!5 = distinct !DISubprogram(name: "hoist_add", linkageName: "hoist_add", scope: null, file: !1, line: 1, type: !6, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !8)
!6 = !DISubroutineType(types: !7)
!7 = !{}
!8 = !{!13}
!10 = !DIBasicType(name: "ty32", size: 32, encoding: DW_ATE_unsigned)
!13 = !DILocalVariable(name: "4", scope: !5, file: !1, line: 5, type: !10)
!20 = !DILocation(line: 1, column: 1, scope: !5)
!21 = !{i32 0, i32 -2147483648}
!22 = !DILocation(line: 2, column: 1, scope: !5)
!23 = !DILocation(line: 3, column: 1, scope: !5)
!24 = !DILocation(line: 4, column: 1, scope: !5)
!25 = !DILocation(line: 5, column: 1, scope: !5)
!26 = !DILocation(line: 6, column: 1, scope: !5)
!27 = !DILocation(line: 7, column: 1, scope: !5)
!28 = !DILocation(line: 8, column: 1, scope: !5)
!29 = !DILocation(line: 9, column: 1, scope: !5)
!30 = !DILocation(line: 10, column: 1, scope: !5)
!31 = !DILocation(line: 11, column: 1, scope: !5)
!32 = !DILocation(line: 12, column: 1, scope: !5)
!33 = !DILocation(line: 13, column: 1, scope: !5)
!34 = !DILocation(line: 14, column: 1, scope: !5)
;.
; CHECK: [[META9]] = !DILocalVariable(name: "4",
; CHECK: [[META16]] = !DILocation(line: 5, column: 1,
;.
45 changes: 45 additions & 0 deletions llvm/test/Transforms/LICM/salvage-hoisted-binop.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,45 @@
; RUN: opt -S -passes=licm %s | FileCheck %s

; Check that hoistBOAssociation() in LICM salvages the dbg_value for the
; hoisted binary operation.

define void @hoist_binop(i64 %c1, i64 %c2) !dbg !5 {
; CHECK-LABEL: define void @hoist_binop(
; CHECK-LABEL: loop:
; CHECK: #dbg_value(!DIArgList(i64 [[INDEX:%.*]], i64 [[C1:%.*]]), [[META9:![0-9]+]], !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_plus, DW_OP_stack_value), [[META13:![0-9]+]])
;
entry:
br label %loop, !dbg !13

loop: ; preds = %loop, %entry
%index = phi i64 [ 0, %entry ], [ %index.next, %loop ], !dbg !14
%step.add = add i64 %index, %c1, !dbg !15
#dbg_value(i64 %step.add, !11, !DIExpression(), !15)
%index.next = add i64 %step.add, %c2, !dbg !16
br label %loop, !dbg !17
}

!llvm.dbg.cu = !{!0}
!llvm.debugify = !{!2, !3}
!llvm.module.flags = !{!4}

!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
!1 = !DIFile(filename: "salvage-hoist-binop.ll", directory: "/")
!2 = !{i32 5}
!3 = !{i32 3}
!4 = !{i32 2, !"Debug Info Version", i32 3}
!5 = distinct !DISubprogram(name: "hoist_binop", linkageName: "hoist_binop", scope: null, file: !1, line: 1, type: !6, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !8)
!6 = !DISubroutineType(types: !7)
!7 = !{}
!8 = !{!11}
!10 = !DIBasicType(name: "ty64", size: 64, encoding: DW_ATE_unsigned)
!11 = !DILocalVariable(name: "2", scope: !5, file: !1, line: 3, type: !10)
!13 = !DILocation(line: 1, column: 1, scope: !5)
!14 = !DILocation(line: 2, column: 1, scope: !5)
!15 = !DILocation(line: 3, column: 1, scope: !5)
!16 = !DILocation(line: 4, column: 1, scope: !5)
!17 = !DILocation(line: 5, column: 1, scope: !5)
;.
; CHECK: [[META9]] = !DILocalVariable(name: "2",
; CHECK: [[META13]] = !DILocation(line: 3, column: 1,
;.
58 changes: 58 additions & 0 deletions llvm/test/Transforms/LICM/salvage-hoisted-gep.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,58 @@
; RUN: opt -S -passes=licm %s | FileCheck %s

; Check that hoistGEP() in LICM salvages the dbg_value for the hoisted
; getelementptr instruction.

define void @hoist_gep(ptr %ptr, i1 %c, i32 %arg) !dbg !5 {
; CHECK-LABEL: define void @hoist_gep(
; CHECK-LABEL: loop:
; CHECK: #dbg_value(!DIArgList(ptr [[PTR:%.*]], i64 [[VAL_EXT:%.*]]), [[META9:![0-9]+]], !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_plus, DW_OP_stack_value), [[META15:![0-9]+]])
;
entry:
%arg.ext = zext i32 %arg to i64, !dbg !16
br label %loop, !dbg !17

loop: ; preds = %loop, %entry
%val = call i32 @get.i32(), !dbg !18
%val.ext = zext i32 %val to i64, !dbg !19
%ptr2 = getelementptr inbounds i8, ptr %ptr, i64 %val.ext, !dbg !20
#dbg_value(ptr %ptr2, !14, !DIExpression(), !20)
%ptr3 = getelementptr i8, ptr %ptr2, i64 %arg.ext, !dbg !21
call void @use(ptr %ptr3), !dbg !22
br i1 %c, label %loop, label %exit, !dbg !23

exit: ; preds = %loop
ret void, !dbg !24
}

declare i32 @get.i32()
declare void @use(ptr)

!llvm.dbg.cu = !{!0}
!llvm.debugify = !{!2, !3}
!llvm.module.flags = !{!4}

!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
!1 = !DIFile(filename: "salvage-hoisted-gep.ll", directory: "/")
!2 = !{i32 9}
!3 = !{i32 5}
!4 = !{i32 2, !"Debug Info Version", i32 3}
!5 = distinct !DISubprogram(name: "hoist_gep", linkageName: "hoist_gep", scope: null, file: !1, line: 1, type: !6, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !8)
!6 = !DISubroutineType(types: !7)
!7 = !{}
!8 = !{!14}
!10 = !DIBasicType(name: "ty64", size: 64, encoding: DW_ATE_unsigned)
!14 = !DILocalVariable(name: "4", scope: !5, file: !1, line: 5, type: !10)
!16 = !DILocation(line: 1, column: 1, scope: !5)
!17 = !DILocation(line: 2, column: 1, scope: !5)
!18 = !DILocation(line: 3, column: 1, scope: !5)
!19 = !DILocation(line: 4, column: 1, scope: !5)
!20 = !DILocation(line: 5, column: 1, scope: !5)
!21 = !DILocation(line: 6, column: 1, scope: !5)
!22 = !DILocation(line: 7, column: 1, scope: !5)
!23 = !DILocation(line: 8, column: 1, scope: !5)
!24 = !DILocation(line: 9, column: 1, scope: !5)
;.
; CHECK: [[META9]] = !DILocalVariable(name: "4",
; CHECK: [[META15]] = !DILocation(line: 5,
;.
70 changes: 70 additions & 0 deletions llvm/test/Transforms/LICM/salvage-hoisted-sub.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,70 @@
; RUN: opt -S -passes=licm %s | FileCheck %s

; Check that hoistSub() in LICM salvages the dbg_value for the hoisted sub
; instruction.

define i32 @hoist_sub(ptr %p, ptr %x_p, ptr %length_p) !dbg !5 {
; CHECK-LABEL: define i32 @hoist_sub(
; CHECK-LABEL: loop:
; CHECK: #dbg_value(!DIArgList(i32 [[X:%.*]], i32 [[IV:%.*]]), [[META9:![0-9]+]], !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_minus, DW_OP_stack_value), [[META16:![0-9]+]])
;
entry:
%x = load i32, ptr %x_p, align 4, !dbg !20, !range !21
%length = load i32, ptr %length_p, align 4, !dbg !22, !range !21
br label %loop, !dbg !23

loop: ; preds = %backedge, %entry
%iv = phi i32 [ 0, %entry ], [ %iv.next, %backedge ], !dbg !24
%arith = sub nsw i32 %x, %iv, !dbg !25
#dbg_value(i32 %arith, !13, !DIExpression(), !25)
%x_check = icmp slt i32 %arith, 4, !dbg !26
br i1 %x_check, label %out_of_bounds, label %backedge, !dbg !27

backedge: ; preds = %loop
%el.ptr = getelementptr i32, ptr %p, i32 %iv, !dbg !28
store i32 1, ptr %el.ptr, align 4, !dbg !29
%iv.next = add nuw nsw i32 %iv, 4, !dbg !30
%loop_cond = icmp slt i32 %iv.next, %length, !dbg !31
br i1 %loop_cond, label %loop, label %exit, !dbg !32

exit: ; preds = %backedge
ret i32 %iv.next, !dbg !33

out_of_bounds: ; preds = %loop
ret i32 -1, !dbg !34
}

!llvm.dbg.cu = !{!0}
!llvm.debugify = !{!2, !3}
!llvm.module.flags = !{!4}

!0 = distinct !DICompileUnit(language: DW_LANG_C, file: !1, producer: "debugify", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug)
!1 = !DIFile(filename: "salvage-hoisted-sub.ll", directory: "/")
!2 = !{i32 14}
!3 = !{i32 8}
!4 = !{i32 2, !"Debug Info Version", i32 3}
!5 = distinct !DISubprogram(name: "hoist_sub", linkageName: "hoist_sub", scope: null, file: !1, line: 1, type: !6, scopeLine: 1, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !8)
!6 = !DISubroutineType(types: !7)
!7 = !{}
!8 = !{!13}
!10 = !DIBasicType(name: "ty32", size: 32, encoding: DW_ATE_unsigned)
!13 = !DILocalVariable(name: "4", scope: !5, file: !1, line: 5, type: !10)
!20 = !DILocation(line: 1, column: 1, scope: !5)
!21 = !{i32 0, i32 -2147483648}
!22 = !DILocation(line: 2, column: 1, scope: !5)
!23 = !DILocation(line: 3, column: 1, scope: !5)
!24 = !DILocation(line: 4, column: 1, scope: !5)
!25 = !DILocation(line: 5, column: 1, scope: !5)
!26 = !DILocation(line: 6, column: 1, scope: !5)
!27 = !DILocation(line: 7, column: 1, scope: !5)
!28 = !DILocation(line: 8, column: 1, scope: !5)
!29 = !DILocation(line: 9, column: 1, scope: !5)
!30 = !DILocation(line: 10, column: 1, scope: !5)
!31 = !DILocation(line: 11, column: 1, scope: !5)
!32 = !DILocation(line: 12, column: 1, scope: !5)
!33 = !DILocation(line: 13, column: 1, scope: !5)
!34 = !DILocation(line: 14, column: 1, scope: !5)
;.
; CHECK: [[META9]] = !DILocalVariable(name: "4",
; CHECK: [[META16]] = !DILocation(line: 5, column: 1,
;.
Loading