Index: cfe/trunk/lib/CodeGen/CGBlocks.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/CGBlocks.cpp
+++ cfe/trunk/lib/CodeGen/CGBlocks.cpp
@@ -619,7 +619,13 @@
 
     // Block captures count as local values and have imprecise semantics.
     // They also can't be arrays, so need to worry about that.
-    if (dtorKind == QualType::DK_objc_strong_lifetime) {
+    //
+    // For const-qualified captures, emit clang.arc.use to ensure the captured
+    // object doesn't get released while we are still depending on its validity
+    // within the block.
+    if (VT.isConstQualified() && VT.getObjCLifetime() == Qualifiers::OCL_Strong)
+      destroyer = CodeGenFunction::emitARCIntrinsicUse;
+    else if (dtorKind == QualType::DK_objc_strong_lifetime) {
       destroyer = CodeGenFunction::destroyARCStrongImprecise;
     } else {
       destroyer = CGF.getDestroyer(dtorKind);
@@ -866,6 +872,12 @@
     } else if (type->isReferenceType()) {
       Builder.CreateStore(src.getPointer(), blockField);
 
+    // If type is const-qualified, copy the value into the block field.
+    } else if (type.isConstQualified() &&
+               type.getObjCLifetime() == Qualifiers::OCL_Strong) {
+      llvm::Value *value = Builder.CreateLoad(src, "captured");
+      Builder.CreateStore(value, blockField);
+
     // If this is an ARC __strong block-pointer variable, don't do a
     // block copy.
     //
Index: cfe/trunk/lib/CodeGen/CGObjC.cpp
===================================================================
--- cfe/trunk/lib/CodeGen/CGObjC.cpp
+++ cfe/trunk/lib/CodeGen/CGObjC.cpp
@@ -2415,6 +2415,12 @@
   CGF.EmitARCDestroyWeak(addr);
 }
 
+void CodeGenFunction::emitARCIntrinsicUse(CodeGenFunction &CGF, Address addr,
+                                          QualType type) {
+  llvm::Value *value = CGF.Builder.CreateLoad(addr);
+  CGF.EmitARCIntrinsicUse(value);
+}
+
 namespace {
   struct CallObjCAutoreleasePoolObject final : EHScopeStack::Cleanup {
     llvm::Value *Token;
Index: cfe/trunk/lib/CodeGen/CodeGenFunction.h
===================================================================
--- cfe/trunk/lib/CodeGen/CodeGenFunction.h
+++ cfe/trunk/lib/CodeGen/CodeGenFunction.h
@@ -3369,6 +3369,7 @@
   static Destroyer destroyARCStrongImprecise;
   static Destroyer destroyARCStrongPrecise;
   static Destroyer destroyARCWeak;
+  static Destroyer emitARCIntrinsicUse;
 
   void EmitObjCAutoreleasePoolPop(llvm::Value *Ptr); 
   llvm::Value *EmitObjCAutoreleasePoolPush();
Index: cfe/trunk/test/CodeGenObjC/arc-blocks.m
===================================================================
--- cfe/trunk/test/CodeGenObjC/arc-blocks.m
+++ cfe/trunk/test/CodeGenObjC/arc-blocks.m
@@ -298,15 +298,11 @@
 // CHECK:      [[D0:%.*]] = getelementptr inbounds [[BLOCK_T]], [[BLOCK_T]]* [[BLOCK]], i32 0, i32 5
 // CHECK:      [[T0:%.*]] = getelementptr inbounds [[BLOCK_T]], [[BLOCK_T]]* [[BLOCK]], i32 0, i32 5
 // CHECK-NEXT: [[T1:%.*]] = load [[TEST8]]*, [[TEST8]]** [[SELF]],
-// CHECK-NEXT: [[T2:%.*]] = bitcast [[TEST8]]* [[T1]] to i8*
-// CHECK-NEXT: [[T3:%.*]] = call i8* @objc_retain(i8* [[T2]])
-// CHECK-NEXT: [[T4:%.*]] = bitcast i8* [[T3]] to [[TEST8]]*
-// CHECK-NEXT: store [[TEST8]]* [[T4]], [[TEST8]]** [[T0]]
+// CHECK-NEXT: store %0* [[T1]], %0** [[T0]]
 // CHECK-NEXT: bitcast [[BLOCK_T]]* [[BLOCK]] to
 // CHECK: call void @test8_helper(
-// CHECK-NEXT: [[T1:%.*]] = load [[TEST8]]*, [[TEST8]]** [[D0]]
-// CHECK-NEXT: [[T2:%.*]] = bitcast [[TEST8]]* [[T1]] to i8*
-// CHECK-NEXT: call void @objc_release(i8* [[T2]])
+// CHECK-NEXT: [[T2:%.*]] = load [[TEST8]]*, [[TEST8]]** [[D0]]
+// CHECK-NEXT: call void (...) @clang.arc.use([[TEST8]]* [[T2]])
 // CHECK: ret void
 
   extern void test8_helper(void (^)(void));
@@ -741,5 +737,31 @@
 // CHECK-NEXT: ret void
 }
 
+// CHECK-LABEL: define void @test20(
+// CHECK: [[XADDR:%.*]] = alloca i8*
+// CHECK-NEXT: [[BLOCK:%.*]] = alloca <[[BLOCKTY:.*]]>
+// CHECK-NEXT: [[RETAINEDX:%.*]] = call i8* @objc_retain(i8* %{{.*}})
+// CHECK-NEXT: store i8* [[RETAINEDX]], i8** [[XADDR]]
+// CHECK-NEXT: [[CAPTUREFIELD:%.*]] = getelementptr inbounds <[[BLOCKTY]]>, <[[BLOCKTY]]>* [[BLOCK]], i32 0, i32 5
+// CHECK: [[BLOCKCAPTURED:%.*]] = getelementptr inbounds <[[BLOCKTY]]>, <[[BLOCKTY]]>* [[BLOCK]], i32 0, i32 5
+// CHECK: [[CAPTURED:%.*]] = load i8*, i8** [[XADDR]]
+// CHECK: store i8* [[CAPTURED]], i8** [[BLOCKCAPTURED]]
+// CHECK: [[CAPTURE:%.*]] = load i8*, i8** [[CAPTUREFIELD]]
+// CHECK-NEXT: call void (...) @clang.arc.use(i8* [[CAPTURE]])
+// CHECK-NEXT: [[X:%.*]] = load i8*, i8** [[XADDR]]
+// CHECK-NEXT: call void @objc_release(i8* [[X]])
+// CHECK-NEXT: ret void
+
+// CHECK-LABEL: define internal void @__copy_helper_block
+// CHECK: [[BLOCKSOURCE:%.*]] = bitcast i8* %{{.*}} to <[[BLOCKTY]]>*
+// CHECK: [[CAPTUREFIELD:%.*]] = getelementptr inbounds <[[BLOCKTY]]>, <[[BLOCKTY]]>* [[BLOCKSOURCE]], i32 0, i32 5
+// CHECK: [[BLOCKCOPYSRC:%.*]] = load i8*, i8** [[CAPTUREFIELD]]
+// CHECK: call i8* @objc_retain(i8* [[BLOCKCOPYSRC]])
+
+void test20_callee(void (^)());
+void test20(const id x) {
+  test20_callee(^{ (void)x; });
+}
+
 // CHECK: attributes [[NUW]] = { nounwind }
 // CHECK-UNOPT: attributes [[NUW]] = { nounwind }
Index: cfe/trunk/test/CodeGenObjC/arc-foreach.m
===================================================================
--- cfe/trunk/test/CodeGenObjC/arc-foreach.m
+++ cfe/trunk/test/CodeGenObjC/arc-foreach.m
@@ -63,11 +63,11 @@
 // CHECK-LP64:      [[D0:%.*]] = getelementptr inbounds [[BLOCK_T]], [[BLOCK_T]]* [[BLOCK]], i32 0, i32 5
 // CHECK-LP64:      [[T0:%.*]] = getelementptr inbounds [[BLOCK_T]], [[BLOCK_T]]* [[BLOCK]], i32 0, i32 5
 // CHECK-LP64-NEXT: [[T1:%.*]] = load i8*, i8** [[X]]
-// CHECK-LP64-NEXT: [[T2:%.*]] = call i8* @objc_retain(i8* [[T1]])
-// CHECK-LP64-NEXT: store i8* [[T2]], i8** [[T0]]
-// CHECK-LP64-NEXT: [[T1:%.*]] = bitcast [[BLOCK_T]]* [[BLOCK]] 
-// CHECK-LP64: call void @use_block(
-// CHECK-LP64-NEXT: call void @objc_storeStrong(i8** [[D0]], i8* null)
+// CHECK-LP64-NEXT: store i8* [[T1]], i8** [[T0]]
+// CHECK-LP64-NEXT: [[BLOCK1:%.*]] = bitcast [[BLOCK_T]]* [[BLOCK]]
+// CHECK-LP64-NEXT: call void @use_block(void ()* [[BLOCK1]])
+// CHECK-LP64-NEXT: [[CAPTURE:%.*]] = load i8*, i8** [[D0]]
+// CHECK-LP64: call void (...) @clang.arc.use(i8* [[CAPTURE]])
 
 // CHECK-LP64:      [[T0:%.*]] = load i8*, i8** @OBJC_SELECTOR_REFERENCES_
 // CHECK-LP64-NEXT: [[T1:%.*]] = bitcast [[ARRAY_T]]* [[SAVED_ARRAY]] to i8*
@@ -200,13 +200,10 @@
 // CHECK-LP64:         [[T0:%.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, [[TY]]* }>, <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, [[TY]]* }>* [[BLOCK]], i32 0, i32 5
 // CHECK-LP64:         [[BC:%.*]] = getelementptr inbounds <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, [[TY]]* }>, <{ i8*, i32, i32, i8*, %struct.__block_descriptor*, [[TY]]* }>* [[BLOCK]], i32 0, i32 5
 // CHECK-LP64:         [[T1:%.*]] = load [[TY]]*, [[TY]]** [[SELF_ADDR]]
-// CHECK-LP64:         [[T2:%.*]] = bitcast [[TY]]* [[T1]] to i8*
-// CHECK-LP64:         [[T3:%.*]] = call i8* @objc_retain(i8* [[T2]])
-// CHECK-LP64:         [[T4:%.*]] = bitcast i8* [[T3]] to [[TY]]*
-// CHECK-LP64:         store [[TY]]* [[T4]], [[TY]]** [[BC]]
+// CHECK-LP64:         store [[TY]]* [[T1]], [[TY]]** [[BC]]
 
-// CHECK-LP64:         [[T5:%.*]] = bitcast [[TY]]** [[T0]] to i8**
-// CHECK-LP64:         call void @objc_storeStrong(i8** [[T5]], i8* null)
+// CHECK-LP64:         [[T5:%.*]] = load [[TY]]*, [[TY]]** [[T0]]
+// CHECK-LP64:         call void (...) @clang.arc.use([[TY]]* [[T5]])
 // CHECK-LP64:         switch i32 {{%.*}}, label %[[UNREACHABLE:.*]] [
 // CHECK-LP64-NEXT:      i32 0, label %[[CLEANUP_CONT:.*]]
 // CHECK-LP64-NEXT:      i32 2, label %[[FORCOLL_END:.*]]