3 files changed, 13 insertions, 24 deletions
diff --git a/clang/lib/CodeGen/CGBlocks.cpp b/clang/lib/CodeGen/CGBlocks.cpp
index 2915dabe541..0bd9d7c506c 100644
--- a/clang/lib/CodeGen/CGBlocks.cpp
+++ b/clang/lib/CodeGen/CGBlocks.cpp
@@ -1293,20 +1293,17 @@ void CodeGenFunction::setBlockContextParameter(const ImplicitParamDecl *D,
                                                llvm::Value *arg) {
   assert(BlockInfo && "not emitting prologue of block invocation function?!");
 
-  llvm::Value *localAddr = nullptr;
-  if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
-    // Allocate a stack slot to let the debug info survive the RA.
-    Address alloc = CreateMemTemp(D->getType(), D->getName() + ".addr");
-    Builder.CreateStore(arg, alloc);
-    localAddr = Builder.CreateLoad(alloc);
-  }
-
+  // Allocate a stack slot like for any local variable to guarantee optimal
+  // debug info at -O0. The mem2reg pass will eliminate it when optimizing.
+  Address alloc = CreateMemTemp(D->getType(), D->getName() + ".addr");
+  Builder.CreateStore(arg, alloc);
   if (CGDebugInfo *DI = getDebugInfo()) {
     if (CGM.getCodeGenOpts().getDebugInfo() >=
         codegenoptions::LimitedDebugInfo) {
       DI->setLocation(D->getLocation());
-      DI->EmitDeclareOfBlockLiteralArgVariable(*BlockInfo, arg, argNum,
-                                               localAddr, Builder);
+      DI->EmitDeclareOfBlockLiteralArgVariable(
+          *BlockInfo, D->getName(), argNum,
+          cast<llvm::AllocaInst>(alloc.getPointer()), Builder);
     }
   }
 
diff --git a/clang/lib/CodeGen/CGDebugInfo.cpp b/clang/lib/CodeGen/CGDebugInfo.cpp
index a73e4a98b3c..3e4acd208f6 100644
--- a/clang/lib/CodeGen/CGDebugInfo.cpp
+++ b/clang/lib/CodeGen/CGDebugInfo.cpp
@@ -3694,9 +3694,9 @@ bool operator<(const BlockLayoutChunk &l, const BlockLayoutChunk &r) {
 }
 
 void CGDebugInfo::EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
-                                                       llvm::Value *Arg,
+                                                       StringRef Name,
                                                        unsigned ArgNo,
-                                                       llvm::Value *LocalAddr,
+                                                       llvm::AllocaInst *Alloca,
                                                        CGBuilderTy &Builder) {
   assert(DebugKind >= codegenoptions::LimitedDebugInfo);
   ASTContext &C = CGM.getContext();
@@ -3828,19 +3828,11 @@ void CGDebugInfo::EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
 
   // Create the descriptor for the parameter.
   auto *debugVar = DBuilder.createParameterVariable(
-      scope, Arg->getName(), ArgNo, tunit, line, type,
+      scope, Name, ArgNo, tunit, line, type,
       CGM.getLangOpts().Optimize, flags);
 
-  if (LocalAddr) {
-    // Insert an llvm.dbg.value into the current block.
-    DBuilder.insertDbgValueIntrinsic(
-        LocalAddr, debugVar, DBuilder.createExpression(),
-        llvm::DebugLoc::get(line, column, scope, CurInlinedAt),
-        Builder.GetInsertBlock());
-  }
-
   // Insert an llvm.dbg.declare into the current block.
-  DBuilder.insertDeclare(Arg, debugVar, DBuilder.createExpression(),
+  DBuilder.insertDeclare(Alloca, debugVar, DBuilder.createExpression(),
                          llvm::DebugLoc::get(line, column, scope, CurInlinedAt),
                          Builder.GetInsertBlock());
 }
diff --git a/clang/lib/CodeGen/CGDebugInfo.h b/clang/lib/CodeGen/CGDebugInfo.h
index 36de231f05f..4f7b7f2a0d9 100644
--- a/clang/lib/CodeGen/CGDebugInfo.h
+++ b/clang/lib/CodeGen/CGDebugInfo.h
@@ -398,8 +398,8 @@ public:
   /// Emit call to \c llvm.dbg.declare for the block-literal argument
   /// to a block invocation function.
   void EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
-                                            llvm::Value *Arg, unsigned ArgNo,
-                                            llvm::Value *LocalAddr,
+                                            StringRef Name, unsigned ArgNo,
+                                            llvm::AllocaInst *LocalAddr,
                                             CGBuilderTy &Builder);
 
   /// Emit information about a global variable.