Index: lib/Transforms/Instrumentation/GCOVProfiling.cpp
===================================================================
--- lib/Transforms/Instrumentation/GCOVProfiling.cpp
+++ lib/Transforms/Instrumentation/GCOVProfiling.cpp
@@ -515,16 +515,6 @@
   return isScopedEHPersonality(Personality);
 }
 
-static bool shouldKeepInEntry(BasicBlock::iterator It) {
-	if (isa<AllocaInst>(*It)) return true;
-	if (isa<DbgInfoIntrinsic>(*It)) return true;
-	if (auto *II = dyn_cast<IntrinsicInst>(It)) {
-		if (II->getIntrinsicID() == llvm::Intrinsic::localescape) return true;
-	}
-
-	return false;
-}
-
 void GCOVProfiler::emitProfileNotes() {
   NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
   if (!CU_Nodes) return;
@@ -558,14 +548,6 @@
       // TODO: Functions using scope-based EH are currently not supported.
       if (isUsingScopeBasedEH(F)) continue;
 
-      // gcov expects every function to start with an entry block that has a
-      // single successor, so split the entry block to make sure of that.
-      BasicBlock &EntryBlock = F.getEntryBlock();
-      BasicBlock::iterator It = EntryBlock.begin();
-      while (shouldKeepInEntry(It))
-        ++It;
-      EntryBlock.splitBasicBlock(It);
-
       Funcs.push_back(make_unique<GCOVFunction>(SP, &F, &out, FunctionIdent++,
                                                 Options.UseCfgChecksum,
                                                 Options.ExitBlockBeforeBody));
@@ -573,13 +555,13 @@
 
       for (auto &BB : F) {
         GCOVBlock &Block = Func.getBlock(&BB);
-        TerminatorInst *TI = BB.getTerminator();
-        if (int successors = TI->getNumSuccessors()) {
-          for (int i = 0; i != successors; ++i) {
-            Block.addEdge(Func.getBlock(TI->getSuccessor(i)));
-          }
-        } else if (isa<ReturnInst>(TI)) {
+        if (succ_begin(&BB) == succ_end(&BB)) {
+          // No successors.
           Block.addEdge(Func.getReturnBlock());
+        } else {
+          for (BasicBlock *Succ : successors(&BB)) {
+            Block.addEdge(Func.getBlock(Succ));
+          }
         }
 
         uint32_t Line = 0;
@@ -640,11 +622,11 @@
       DenseMap<std::pair<BasicBlock *, BasicBlock *>, unsigned> EdgeToCounter;
       unsigned Edges = 0;
       for (auto &BB : F) {
-        TerminatorInst *TI = BB.getTerminator();
-        if (isa<ReturnInst>(TI)) {
+        if (succ_begin(&BB) == succ_end(&BB)) {
+          // No successors.
           EdgeToCounter[{&BB, nullptr}] = Edges++;
         } else {
-          for (BasicBlock *Succ : successors(TI)) {
+          for (BasicBlock *Succ : successors(&BB)) {
             EdgeToCounter[{&BB, Succ}] = Edges++;
           }
         }
@@ -683,18 +665,18 @@
           Value *Count = Builder.CreateLoad(Phi);
           Count = Builder.CreateAdd(Count, Builder.getInt64(1));
           Builder.CreateStore(Count, Phi);
+        }
 
-          TerminatorInst *TI = BB.getTerminator();
-          if (isa<ReturnInst>(TI)) {
-            auto It = EdgeToCounter.find({&BB, nullptr});
-            assert(It != EdgeToCounter.end());
-            const unsigned Edge = It->second;
-            Value *Counter =
-                Builder.CreateConstInBoundsGEP2_64(Counters, 0, Edge);
-            Value *Count = Builder.CreateLoad(Counter);
-            Count = Builder.CreateAdd(Count, Builder.getInt64(1));
-            Builder.CreateStore(Count, Counter);
-          }
+        if (succ_begin(&BB) == succ_end(&BB)) {
+          IRBuilder<> Builder(&*BB.getFirstInsertionPt());
+          auto It = EdgeToCounter.find({&BB, nullptr});
+          assert(It != EdgeToCounter.end());
+          const unsigned Edge = It->second;
+          Value *Counter =
+              Builder.CreateConstInBoundsGEP2_64(Counters, 0, Edge);
+          Value *Count = Builder.CreateLoad(Counter);
+          Count = Builder.CreateAdd(Count, Builder.getInt64(1));
+          Builder.CreateStore(Count, Counter);
         }
       }
     }
Index: test/Transforms/GCOVProfiling/Inputs/empty-function-1.ll
===================================================================
--- /dev/null
+++ test/Transforms/GCOVProfiling/Inputs/empty-function-1.ll
@@ -0,0 +1,3 @@
+define void @empty1() {
+  ret void
+}
Index: test/Transforms/GCOVProfiling/Inputs/empty-function-2.ll
===================================================================
--- /dev/null
+++ test/Transforms/GCOVProfiling/Inputs/empty-function-2.ll
@@ -0,0 +1,3 @@
+define void @empty2() {
+  ret void
+}
Index: test/Transforms/GCOVProfiling/multiple-cus.ll
===================================================================
--- /dev/null
+++ test/Transforms/GCOVProfiling/multiple-cus.ll
@@ -0,0 +1,5 @@
+; RUN: opt -debugify %S/Inputs/empty-function-1.ll -o %t.1.bc
+; RUN: opt -debugify %S/Inputs/empty-function-2.ll -o %t.2.bc
+; RUN: llvm-link %t.1.bc %t.2.bc -o %t.lto.bc
+; RUN: opt -S -insert-gcov-profiling %t.lto.bc -o -
+; TODO: Check that the IR is correct.
Index: test/Transforms/GCOVProfiling/return-block.ll
===================================================================
--- test/Transforms/GCOVProfiling/return-block.ll
+++ test/Transforms/GCOVProfiling/return-block.ll
@@ -78,7 +78,7 @@
 ; RETURN-LAST:       Destination Edges
 ; RETURN-SECOND-NOT: Destination Edges
 ; CHECK: Block : 2 Counter : 0
-; CHECK: Block : 4 Counter : 0
+; CHECK: Block : 3 Counter : 0
 ; RETURN-LAST-NOT: Destination Edges
 ; RETURN-SECOND:   Destination Edges
 ; CHECK-NOT: Block :