Revert r281895 "Add @llvm.dbg.value entries for the phi node created by -mem2reg"

(And follow-up r281964.)

It caused PR30468.

llvm-svn: 282077

llvm/include/llvm/Transforms/Utils/Local.h

@@ -32,7 +32,6 @@ class BranchInst;
 class Instruction;
 class CallInst;
 class DbgDeclareInst;
-class DbgValueInst;
 class StoreInst;
 class LoadInst;
 class Value;
@@ -49,8 +48,6 @@ class LazyValueInfo;
 
 template<typename T> class SmallVectorImpl;
 
-typedef SmallVector<DbgValueInst *, 1> DbgValueList;
-
 //===----------------------------------------------------------------------===//
 //  Local constant propagation.
 //
@@ -258,19 +255,14 @@ Value *EmitGEPOffset(IRBuilderTy *Builder, const DataLayout &DL, User *GEP,
 
 /// Inserts a llvm.dbg.value intrinsic before a store to an alloca'd value
 /// that has an associated llvm.dbg.decl intrinsic.
-void ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
+bool ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
                                      StoreInst *SI, DIBuilder &Builder);
 
 /// Inserts a llvm.dbg.value intrinsic before a load of an alloca'd value
 /// that has an associated llvm.dbg.decl intrinsic.
-void ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
+bool ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
                                      LoadInst *LI, DIBuilder &Builder);
 
-/// Inserts a llvm.dbg.value intrinsic after a phi of an alloca'd value
-/// that has an associated llvm.dbg.decl intrinsic.
-void ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
-                                     PHINode *LI, DIBuilder &Builder);
-
 /// Lowers llvm.dbg.declare intrinsics into appropriate set of
 /// llvm.dbg.value intrinsics.
 bool LowerDbgDeclare(Function &F);
@@ -278,9 +270,6 @@ bool LowerDbgDeclare(Function &F);
 /// Finds the llvm.dbg.declare intrinsic corresponding to an alloca, if any.
 DbgDeclareInst *FindAllocaDbgDeclare(Value *V);
 
-/// Finds the llvm.dbg.value intrinsics corresponding to an alloca, if any.
-void FindAllocaDbgValues(DbgValueList &DbgValues, Value *V);
-
 /// Replaces llvm.dbg.declare instruction when the address it describes
 /// is replaced with a new value. If Deref is true, an additional DW_OP_deref is
 /// prepended to the expression. If Offset is non-zero, a constant displacement

llvm/lib/Transforms/Utils/Local.cpp

@@ -1053,27 +1053,9 @@ static bool LdStHasDebugValue(DILocalVariable *DIVar, DIExpression *DIExpr,
   return false;
 }
 
-/// See if there is a dbg.value intrinsic for DIVar for the PHI node.
-static bool PhiHasDebugValue(DILocalVariable *DIVar, 
-                             DIExpression *DIExpr,
-                             PHINode *APN) {
-  // Since we can't guarantee that the original dbg.declare instrinsic
-  // is removed by LowerDbgDeclare(), we need to make sure that we are
-  // not inserting the same dbg.value intrinsic over and over.
-  DbgValueList DbgValues;
-  FindAllocaDbgValues(DbgValues, APN);
-  for (auto DVI : DbgValues) {
-    assert (DVI->getValue() == APN);
-    assert (DVI->getOffset() == 0);
-    if ((DVI->getVariable() == DIVar) && (DVI->getExpression() == DIExpr))
-      return true;
-  }
-  return false;
-}
-
 /// Inserts a llvm.dbg.value intrinsic before a store to an alloca'd value
 /// that has an associated llvm.dbg.decl intrinsic.
-void llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
+bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
                                            StoreInst *SI, DIBuilder &Builder) {
   auto *DIVar = DDI->getVariable();
   auto *DIExpr = DDI->getExpression();
@@ -1114,18 +1096,19 @@ void llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
   } else if (!LdStHasDebugValue(DIVar, DIExpr, SI))
     Builder.insertDbgValueIntrinsic(SI->getOperand(0), 0, DIVar, DIExpr,
                                     DDI->getDebugLoc(), SI);
+  return true;
 }
 
 /// Inserts a llvm.dbg.value intrinsic before a load of an alloca'd value
 /// that has an associated llvm.dbg.decl intrinsic.
-void llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
+bool llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
                                            LoadInst *LI, DIBuilder &Builder) {
   auto *DIVar = DDI->getVariable();
   auto *DIExpr = DDI->getExpression();
   assert(DIVar && "Missing variable");
 
   if (LdStHasDebugValue(DIVar, DIExpr, LI))
-    return;
+    return true;
 
   // We are now tracking the loaded value instead of the address. In the
   // future if multi-location support is added to the IR, it might be
@@ -1134,22 +1117,7 @@ void llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
   Instruction *DbgValue = Builder.insertDbgValueIntrinsic(
       LI, 0, DIVar, DIExpr, DDI->getDebugLoc(), (Instruction *)nullptr);
   DbgValue->insertAfter(LI);
-}
+  return true;
-
-/// Inserts a llvm.dbg.value intrinsic after a phi 
-/// that has an associated llvm.dbg.decl intrinsic.
-void llvm::ConvertDebugDeclareToDebugValue(DbgDeclareInst *DDI,
-                                           PHINode *APN, DIBuilder &Builder) {
-  auto *DIVar = DDI->getVariable();
-  auto *DIExpr = DDI->getExpression();
-  assert(DIVar && "Missing variable");
-
-  if (PhiHasDebugValue(DIVar, DIExpr, APN))
-    return;
-
-  Instruction *DbgValue = Builder.insertDbgValueIntrinsic(
-      APN, 0, DIVar, DIExpr, DDI->getDebugLoc(), (Instruction *)nullptr);
-  DbgValue->insertBefore(&*APN->getParent()->getFirstInsertionPt());
 }
 
 /// Determine whether this alloca is either a VLA or an array.
@@ -1219,16 +1187,6 @@ DbgDeclareInst *llvm::FindAllocaDbgDeclare(Value *V) {
   return nullptr;
 }
 
-/// FindAllocaDbgValues - Finds the llvm.dbg.value intrinsics describing the
-/// alloca 'V', if any.
-void llvm::FindAllocaDbgValues(DbgValueList &DbgValues, Value *V) {
-  if (auto *L = LocalAsMetadata::getIfExists(V))
-    if (auto *MDV = MetadataAsValue::getIfExists(V->getContext(), L))
-      for (User *U : MDV->users())
-        if (DbgValueInst *DVI = dyn_cast<DbgValueInst>(U))
-          DbgValues.push_back(DVI);
-}
-
 static void DIExprAddDeref(SmallVectorImpl<uint64_t> &Expr) {
   Expr.push_back(dwarf::DW_OP_deref);
 }

llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp

@@ -907,8 +907,6 @@ NextIteration:
 
         // The currently active variable for this block is now the PHI.
         IncomingVals[AllocaNo] = APN;
-        if (DbgDeclareInst *DDI = AllocaDbgDeclares[AllocaNo])
-          ConvertDebugDeclareToDebugValue(DDI, APN, DIB);
 
         // Get the next phi node.
         ++PNI;

llvm/test/Transforms/Util/mem2reg-dbg.ll

@@ -1,76 +0,0 @@
-; RUN: opt -mem2reg -S < %s | FileCheck %s
-
-; Test that a @llvm.dbg.value node is created to describe the value returned by a phi node when
-; lowering a @llvm.dbg.declare node
-
-; Created from the C code, compiled with -O0 -g:
-;
-; int func(int a)
-; {
-;         int c = 1;
-;         if (a < 0 ) {
-;                 c = 12;
-;         }
-;         return c;
-; }
-
-; Function Attrs: nounwind
-define i32 @func(i32 %a) #0 !dbg !8 {
-entry:
-  %a.addr = alloca i32, align 4
-  %c = alloca i32, align 4
-  store i32 %a, i32* %a.addr, align 4
-  call void @llvm.dbg.declare(metadata i32* %a.addr, metadata !12, metadata !13), !dbg !14
-  call void @llvm.dbg.declare(metadata i32* %c, metadata !15, metadata !13), !dbg !16
-  store i32 1, i32* %c, align 4, !dbg !16
-  %0 = load i32, i32* %a.addr, align 4, !dbg !17
-  %cmp = icmp slt i32 %0, 0, !dbg !19
-  br i1 %cmp, label %if.then, label %if.end, !dbg !20
-
-if.then:                                          ; preds = %entry
-  store i32 12, i32* %c, align 4, !dbg !21
-  br label %if.end, !dbg !23
-
-if.end:                                           ; preds = %if.then, %entry
-  %1 = load i32, i32* %c, align 4, !dbg !24
-; CHECK: [[PHI:%.*]] = phi i32 [ 12, {{.*}} ], [ 1, {{.*}} ]
-; CHECK-NEXT: call void @llvm.dbg.value(metadata i32 [[PHI]], i64 0, metadata !15, metadata !13), !dbg !16
-  ret i32 %1, !dbg !25
-}
-
-; Function Attrs: nounwind readnone
-declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
-
-attributes #1 = { nounwind readnone }
-
-!llvm.dbg.cu = !{!0}
-!llvm.module.flags = !{!3, !4, !5, !6}
-!llvm.ident = !{!7}
-
-!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
-!1 = !DIFile(filename: "a.c", directory: "/tmp")
-!2 = !{}
-!3 = !{i32 2, !"Dwarf Version", i32 4}
-!4 = !{i32 2, !"Debug Info Version", i32 3}
-!5 = !{i32 1, !"wchar_size", i32 4}
-!6 = !{i32 1, !"min_enum_size", i32 4}
-!7 = !{!"clang"}
-!8 = distinct !DISubprogram(name: "func", scope: !1, file: !1, line: 1, type: !9, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: false, unit: !0, variables: !2)
-!9 = !DISubroutineType(types: !10)
-!10 = !{!11, !11}
-!11 = !DIBasicType(name: "int", size: 32, align: 32, encoding: DW_ATE_signed)
-!12 = !DILocalVariable(name: "a", arg: 1, scope: !8, file: !1, line: 1, type: !11)
-!13 = !DIExpression()
-!14 = !DILocation(line: 1, column: 14, scope: !8)
-!15 = !DILocalVariable(name: "c", scope: !8, file: !1, line: 3, type: !11)
-!16 = !DILocation(line: 3, column: 6, scope: !8)
-!17 = !DILocation(line: 4, column: 6, scope: !18)
-!18 = distinct !DILexicalBlock(scope: !8, file: !1, line: 4, column: 6)
-!19 = !DILocation(line: 4, column: 8, scope: !18)
-!20 = !DILocation(line: 4, column: 6, scope: !8)
-!21 = !DILocation(line: 5, column: 5, scope: !22)
-!22 = distinct !DILexicalBlock(scope: !18, file: !1, line: 4, column: 14)
-!23 = !DILocation(line: 6, column: 2, scope: !22)
-!24 = !DILocation(line: 7, column: 9, scope: !8)
-!25 = !DILocation(line: 7, column: 2, scope: !8)
-