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[DebugInfo] Clone dbg.values in SimplifyCFG like normal instructions #72526

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[DebugInfo] Clone dbg.values in SimplifyCFG like normal instructions #72526

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a31c7e1
[DebugInfo] Clone dbg.values in SimplifyCFG like normal instructions
jmorse Nov 16, 2023
4b749c4
Don't add dbg.values to the remap-map (it's wasteful),
jmorse Nov 16, 2023
5246cf6
clang-format
jmorse Nov 16, 2023
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21 changes: 8 additions & 13 deletions llvm/lib/Transforms/Utils/SimplifyCFG.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1101,12 +1101,13 @@ static void CloneInstructionsIntoPredecessorBlockAndUpdateSSAUses(
// Note that there may be multiple predecessor blocks, so we cannot move
// bonus instructions to a predecessor block.
for (Instruction &BonusInst : *BB) {
if (isa<DbgInfoIntrinsic>(BonusInst) || BonusInst.isTerminator())
if (BonusInst.isTerminator())
continue;

Instruction *NewBonusInst = BonusInst.clone();

if (PTI->getDebugLoc() != NewBonusInst->getDebugLoc()) {
if (!isa<DbgInfoIntrinsic>(BonusInst) &&
PTI->getDebugLoc() != NewBonusInst->getDebugLoc()) {
// Unless the instruction has the same !dbg location as the original
// branch, drop it. When we fold the bonus instructions we want to make
// sure we reset their debug locations in order to avoid stepping on
Expand All @@ -1116,7 +1117,6 @@ static void CloneInstructionsIntoPredecessorBlockAndUpdateSSAUses(

RemapInstruction(NewBonusInst, VMap,
RF_NoModuleLevelChanges | RF_IgnoreMissingLocals);
VMap[&BonusInst] = NewBonusInst;

// If we speculated an instruction, we need to drop any metadata that may
// result in undefined behavior, as the metadata might have been valid
Expand All @@ -1126,8 +1126,13 @@ static void CloneInstructionsIntoPredecessorBlockAndUpdateSSAUses(
NewBonusInst->dropUBImplyingAttrsAndMetadata();

NewBonusInst->insertInto(PredBlock, PTI->getIterator());

if (isa<DbgInfoIntrinsic>(BonusInst))
continue;

NewBonusInst->takeName(&BonusInst);
BonusInst.setName(NewBonusInst->getName() + ".old");
VMap[&BonusInst] = NewBonusInst;

// Update (liveout) uses of bonus instructions,
// now that the bonus instruction has been cloned into predecessor.
Expand Down Expand Up @@ -3744,16 +3749,6 @@ static bool performBranchToCommonDestFolding(BranchInst *BI, BranchInst *PBI,
PBI->setCondition(
createLogicalOp(Builder, Opc, PBI->getCondition(), BICond, "or.cond"));

// Copy any debug value intrinsics into the end of PredBlock.
for (Instruction &I : *BB) {
if (isa<DbgInfoIntrinsic>(I)) {
Instruction *NewI = I.clone();
RemapInstruction(NewI, VMap,
RF_NoModuleLevelChanges | RF_IgnoreMissingLocals);
NewI->insertBefore(PBI);
}
}

++NumFoldBranchToCommonDest;
return true;
}
Expand Down
34 changes: 21 additions & 13 deletions llvm/test/Transforms/SimplifyCFG/branch-fold-dbg.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -8,23 +8,26 @@
define i1 @foo(i32) nounwind ssp !dbg !0 {
; CHECK-LABEL: @foo(
; CHECK-NEXT: Entry:
; CHECK-NEXT: [[TMP1:%.*]] = icmp slt i32 [[TMP0:%.*]], 0
; CHECK-NEXT: [[TMP2:%.*]] = icmp sgt i32 [[TMP0]], 4
; CHECK-NEXT: [[OR_COND:%.*]] = or i1 [[TMP1]], [[TMP2]]
; CHECK-NEXT: br i1 [[OR_COND]], label [[COMMON_RET:%.*]], label [[BB2:%.*]]
; CHECK-NEXT: [[TMP1:%.*]] = icmp slt i32 [[TMP0:%.*]], 0, !dbg [[DBG7:![0-9]+]]
; CHECK-NEXT: [[TMP2:%.*]] = icmp sgt i32 [[TMP0]], 4, !dbg [[DBG7]]
; CHECK-NEXT: [[OR_COND:%.*]] = or i1 [[TMP1]], [[TMP2]], !dbg [[DBG7]]
; CHECK-NEXT: br i1 [[OR_COND]], label [[COMMON_RET:%.*]], label [[BB2:%.*]], !dbg [[DBG7]]
; CHECK: BB2:
; CHECK-NEXT: [[TMP3:%.*]] = shl i32 1, [[TMP0]]
; CHECK-NEXT: [[TMP4:%.*]] = and i32 [[TMP3]], 31
; CHECK-NEXT: [[TMP5:%.*]] = icmp eq i32 [[TMP4]], 0
; CHECK-NEXT: [[TMP3:%.*]] = shl i32 1, [[TMP0]], !dbg [[DBG7]]
; CHECK-NEXT: [[TMP4:%.*]] = and i32 [[TMP3]], 31, !dbg [[DBG7]]
; CHECK-NEXT: [[TMP5:%.*]] = icmp eq i32 [[TMP4]], 0, !dbg [[DBG7]]
; CHECK-NEXT: call void @llvm.dbg.value(metadata ptr null, metadata [[META8:![0-9]+]], metadata !DIExpression()), !dbg [[DBG13:![0-9]+]]
; CHECK-NEXT: [[TMP6:%.*]] = getelementptr inbounds [5 x %0], ptr @[[GLOB0:[0-9]+]], i32 0, i32 [[TMP0]]
; CHECK-NEXT: call void @llvm.dbg.value(metadata ptr [[TMP6]], metadata [[META8]], metadata !DIExpression()), !dbg [[DBG13]]
; CHECK-NEXT: [[TMP7:%.*]] = icmp eq ptr [[TMP6]], null
; CHECK-NEXT: [[OR_COND2:%.*]] = select i1 [[TMP5]], i1 true, i1 [[TMP7]]
; CHECK-NEXT: call void @llvm.dbg.value(metadata ptr [[TMP6]], metadata [[META8]], metadata !DIExpression()), !dbg [[DBG13]]
; CHECK-NEXT: [[OR_COND2:%.*]] = select i1 [[TMP5]], i1 true, i1 [[TMP7]], !dbg [[DBG7]]
; CHECK-NEXT: [[TMP8:%.*]] = icmp slt i32 [[TMP0]], 0
; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[OR_COND2]], i1 false, i1 [[TMP8]]
; CHECK-NEXT: br label [[COMMON_RET]]
; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[OR_COND2]], i1 false, i1 [[TMP8]], !dbg [[DBG7]]
; CHECK-NEXT: br label [[COMMON_RET]], !dbg [[DBG7]]
; CHECK: common.ret:
; CHECK-NEXT: [[COMMON_RET_OP:%.*]] = phi i1 [ false, [[ENTRY:%.*]] ], [ [[SPEC_SELECT]], [[BB2]] ]
; CHECK-NEXT: ret i1 [[COMMON_RET_OP]]
; CHECK-NEXT: ret i1 [[COMMON_RET_OP]], !dbg [[DBG14:![0-9]+]]
;
Entry:
%1 = icmp slt i32 %0, 0, !dbg !5
Expand All @@ -42,9 +45,11 @@ BB2: ; preds = %BB1


BB3: ; preds = %BB2
call void @llvm.dbg.value(metadata ptr null, metadata !7, metadata !DIExpression()), !dbg !12
%6 = getelementptr inbounds [5 x %0], ptr @0, i32 0, i32 %0, !dbg !6
call void @llvm.dbg.value(metadata ptr %6, metadata !7, metadata !{}), !dbg !12
call void @llvm.dbg.value(metadata ptr %6, metadata !7, metadata !DIExpression()), !dbg !12
%7 = icmp eq ptr %6, null, !dbg !13
call void @llvm.dbg.value(metadata ptr %6, metadata !7, metadata !DIExpression()), !dbg !12
br i1 %7, label %BB5, label %BB4, !dbg !13

BB4: ; preds = %BB3
Expand All @@ -58,12 +63,13 @@ BB5: ; preds = %BB3, %BB2, %BB1, %E
declare void @llvm.dbg.value(metadata, metadata, metadata) nounwind readnone

!llvm.dbg.cu = !{!2}
!llvm.module.flags = !{!16, !17}

!0 = distinct !DISubprogram(name: "foo", line: 231, isLocal: false, isDefinition: true, virtualIndex: 6, flags: DIFlagPrototyped, isOptimized: false, unit: !2, file: !15, scope: !1, type: !3)
!1 = !DIFile(filename: "a.c", directory: "/private/tmp")
!2 = distinct !DICompileUnit(language: DW_LANG_C99, producer: "clang (trunk 129006)", isOptimized: true, emissionKind: FullDebug, file: !15, enums: !4, retainedTypes: !4)
!3 = !DISubroutineType(types: !4)
!4 = !{null}
!4 = !{}
!5 = !DILocation(line: 131, column: 2, scope: !0)
!6 = !DILocation(line: 134, column: 2, scope: !0)
!7 = !DILocalVariable(name: "bar", line: 232, scope: !8, file: !1, type: !9)
Expand All @@ -75,3 +81,5 @@ declare void @llvm.dbg.value(metadata, metadata, metadata) nounwind readnone
!13 = !DILocation(line: 234, column: 2, scope: !8)
!14 = !DILocation(line: 274, column: 1, scope: !8)
!15 = !DIFile(filename: "a.c", directory: "/private/tmp")
!16 = !{i32 1, !"Debug Info Version", i32 3}
!17 = !{i32 2, !"Dwarf Version", i32 4}