[InstCombine][DebugInfo] Update debug value uses in freelyInvertAllUsersOf (#137013)

This patch updates all debug value uses in `freelyInvertAllUsersOf` by
inserting `DW_OP_not` at the front of the DIExpression.

Related issue: #71065

Author: dtcxzyw

llvm/lib/Transforms/InstCombine/InstructionCombining.cpp

@@ -1396,6 +1396,26 @@ void InstCombinerImpl::freelyInvertAllUsersOf(Value *I, Value *IgnoredUser) {
                        "canFreelyInvertAllUsersOf() ?");
     }
   }
+
+  // Update pre-existing debug value uses.
+  SmallVector<DbgValueInst *, 4> DbgValues;
+  SmallVector<DbgVariableRecord *, 4> DbgVariableRecords;
+  llvm::findDbgValues(DbgValues, I, &DbgVariableRecords);
+
+  auto InvertDbgValueUse = [&](auto *DbgVal) {
+    SmallVector<uint64_t, 1> Ops = {dwarf::DW_OP_not};
+    for (unsigned Idx = 0, End = DbgVal->getNumVariableLocationOps();
+         Idx != End; ++Idx)
+      if (DbgVal->getVariableLocationOp(Idx) == I)
+        DbgVal->setExpression(
+            DIExpression::appendOpsToArg(DbgVal->getExpression(), Ops, Idx));
+  };
+
+  for (DbgValueInst *DVI : DbgValues)
+    InvertDbgValueUse(DVI);
+
+  for (DbgVariableRecord *DVR : DbgVariableRecords)
+    InvertDbgValueUse(DVR);
 }
 
 /// Given a 'sub' instruction, return the RHS of the instruction if the LHS is a

llvm/test/Transforms/InstCombine/debuginfo-invert.ll

@@ -0,0 +1,60 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+; RUN: opt -passes=instcombine -S %s -o - | FileCheck %s
+
+; Make sure that the DIExpression is updated correctly after InstCombinerImpl::freelyInvertAllUsersOf.
+
+define i32 @test(i32 noundef %x, i32 noundef %y) !dbg !10 {
+; CHECK-LABEL: define i32 @test(
+; CHECK-SAME: i32 noundef [[X:%.*]], i32 noundef [[Y:%.*]]) !dbg [[DBG10:![0-9]+]] {
+; CHECK-NEXT:  [[ENTRY:.*:]]
+; CHECK-NEXT:    [[CMP_NOT:%.*]] = icmp eq i32 [[X]], 0
+; CHECK-NEXT:      #dbg_value(i1 [[CMP_NOT]], [[META15:![0-9]+]], !DIExpression(DW_OP_not, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 32, DW_ATE_unsigned, DW_OP_stack_value), [[META16:![0-9]+]])
+; CHECK-NEXT:      #dbg_value(!DIArgList(i1 false, i1 [[CMP_NOT]]), [[META17:![0-9]+]], !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_not, DW_OP_or, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 8, DW_ATE_unsigned, DW_OP_stack_value), [[META16]])
+; CHECK-NEXT:    [[TMP0:%.*]] = and i32 [[Y]], 1
+; CHECK-NEXT:    [[AND:%.*]] = select i1 [[CMP_NOT]], i32 0, i32 [[TMP0]]
+; CHECK-NEXT:    ret i32 [[AND]]
+;
+entry:
+  %cmp = icmp ne i32 %x, 0
+  %conv = zext i1 %cmp to i32
+    #dbg_value(i32 %conv, !15, !DIExpression(), !16)
+    #dbg_value(!DIArgList(i1 false, i1 %cmp), !17, !DIExpression(DW_OP_LLVM_arg, 0, DW_OP_LLVM_arg, 1, DW_OP_or, DW_OP_LLVM_convert, 1, DW_ATE_unsigned, DW_OP_LLVM_convert, 8, DW_ATE_unsigned, DW_OP_stack_value), !18)
+  %and = and i32 %conv, %y
+  ret i32 %and
+}
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!2, !3, !4, !5, !6, !7, !8}
+!llvm.ident = !{!9}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C11, file: !1, producer: "clang version 21.0.0git", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "test.c", directory: "/", checksumkind: CSK_MD5, checksum: "b2d9ffc7905684d8b7c3b52a3136e57c")
+!2 = !{i32 7, !"Dwarf Version", i32 5}
+!3 = !{i32 2, !"Debug Info Version", i32 3}
+!4 = !{i32 1, !"wchar_size", i32 4}
+!5 = !{i32 8, !"PIC Level", i32 2}
+!6 = !{i32 7, !"PIE Level", i32 2}
+!7 = !{i32 7, !"uwtable", i32 2}
+!8 = !{i32 7, !"debug-info-assignment-tracking", i1 true}
+!9 = !{!"clang version 21.0.0git"}
+!10 = distinct !DISubprogram(name: "test", scope: !1, file: !1, line: 1, type: !11, scopeLine: 1, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: !0, retainedNodes: !14)
+!11 = !DISubroutineType(types: !12)
+!12 = !{!13, !13, !13}
+!13 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+!14 = !{!15}
+!15 = !DILocalVariable(name: "z", scope: !10, file: !1, line: 2, type: !13)
+!16 = !DILocation(line: 0, scope: !10)
+!17 = !DILocalVariable(name: "w", scope: !10, file: !1, line: 3, type: !13)
+!18 = !DILocation(line: 0, scope: !10)
+;.
+; CHECK: [[META0:![0-9]+]] = distinct !DICompileUnit(language: DW_LANG_C11, file: [[META1:![0-9]+]], producer: "{{.*}}clang version {{.*}}", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, splitDebugInlining: false, nameTableKind: None)
+; CHECK: [[META1]] = !DIFile(filename: "{{.*}}test.c", directory: {{.*}})
+; CHECK: [[DBG10]] = distinct !DISubprogram(name: "test", scope: [[META1]], file: [[META1]], line: 1, type: [[META11:![0-9]+]], scopeLine: 1, flags: DIFlagPrototyped | DIFlagAllCallsDescribed, spFlags: DISPFlagDefinition | DISPFlagOptimized, unit: [[META0]], retainedNodes: [[META14:![0-9]+]])
+; CHECK: [[META11]] = !DISubroutineType(types: [[META12:![0-9]+]])
+; CHECK: [[META12]] = !{[[META13:![0-9]+]], [[META13]], [[META13]]}
+; CHECK: [[META13]] = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+; CHECK: [[META14]] = !{[[META15]]}
+; CHECK: [[META15]] = !DILocalVariable(name: "z", scope: [[DBG10]], file: [[META1]], line: 2, type: [[META13]])
+; CHECK: [[META16]] = !DILocation(line: 0, scope: [[DBG10]])
+; CHECK: [[META17]] = !DILocalVariable(name: "w", scope: [[DBG10]], file: [[META1]], line: 3, type: [[META13]])
+;.