Index: lib/CodeGen/SafeStack.cpp
===================================================================
--- lib/CodeGen/SafeStack.cpp
+++ lib/CodeGen/SafeStack.cpp
@@ -58,6 +58,11 @@
                           "Non-thread-local storage"),
                clEnumValEnd));
 
+static cl::opt<bool> SubroutineAccessAsUnsafe("safe-stack-subr-acc-as-unsafe",
+    cl::Hidden, cl::init(false),
+    cl::desc("Allocate memory on the unsafe stack if a pointer to it is passed "
+             "to a subroutine"));
+
 namespace llvm {
 
 STATISTIC(NumFunctions, "Total number of functions");
@@ -313,6 +318,9 @@
           continue;
         }
 
+        if (SubroutineAccessAsUnsafe)
+          return false;
+
         // LLVM 'nocapture' attribute is only set for arguments whose address
         // is not stored, passed around, or used in any other non-trivial way.
         // We assume that passing a pointer to an object as a 'nocapture
Index: test/Transforms/SafeStack/call.ll
===================================================================
--- test/Transforms/SafeStack/call.ll
+++ test/Transforms/SafeStack/call.ll
@@ -1,5 +1,7 @@
 ; RUN: opt -safe-stack -S -mtriple=i386-pc-linux-gnu < %s -o - | FileCheck %s
 ; RUN: opt -safe-stack -S -mtriple=x86_64-pc-linux-gnu < %s -o - | FileCheck %s
+; RUN: opt -safe-stack -safe-stack-subr-acc-as-unsafe -S -mtriple=i386-pc-linux-gnu < %s -o - | FileCheck -check-prefix=SUBR-ACC-AS-UNSAFE %s
+; RUN: opt -safe-stack -safe-stack-subr-acc-as-unsafe -S -mtriple=x86_64-pc-linux-gnu < %s -o - | FileCheck -check-prefix=SUBR-ACC-AS-UNSAFE %s
 
 @.str = private unnamed_addr constant [4 x i8] c"%s\0A\00", align 1
 
@@ -79,11 +81,12 @@
   ret void
 }
 
-; Arg0 is readnone, arg1 is not. Pass alloca ptr as arg0 -> safe
+; Arg0 is readnone, arg1 is not. Pass alloca ptr as arg0 -> safe unless -safe-stack-subr-acc-as-unsafe is set.
 define void @call_readnone0_0(i64 %len) safestack {
 entry:
   ; CHECK-LABEL: define void @call_readnone0_0
   ; CHECK-NOT: @__safestack_unsafe_stack_ptr
+  ; SUBR-ACC-AS-UNSAFE: @__safestack_unsafe_stack_ptr
   ; CHECK: ret void
   %q = alloca [10 x i8], align 1
   %arraydecay = getelementptr inbounds [10 x i8], [10 x i8]* %q, i32 0, i32 0