diff --git a/lib/Target/ARM/Thumb2SizeReduction.cpp b/lib/Target/ARM/Thumb2SizeReduction.cpp
index 89232f3f7a7..a44ac07cd67 100644
--- a/lib/Target/ARM/Thumb2SizeReduction.cpp
+++ b/lib/Target/ARM/Thumb2SizeReduction.cpp
@@ -58,7 +58,7 @@ namespace {
     { ARM::t2ADDri, ARM::tADDi3,  ARM::tADDi8,   3,   8,    1,   1,  0,0, 0 },
     { ARM::t2ADDrr, ARM::tADDrr,  ARM::tADDhirr, 0,   0,    1,   0,  0,1, 0 },
     // Note: immediate scale is 4.
-    { ARM::t2ADDrSPi,ARM::tADDrSPi,0,            8,   0,    1,   0,  1,0, 0 },
+    { ARM::t2ADDrSPi,ARM::tADDrSPi,0,            8,   0,    1,   0,  1,0, 1 },
     { ARM::t2ADDSri,ARM::tADDi3,  ARM::tADDi8,   3,   8,    1,   1,  2,2, 1 },
     { ARM::t2ADDSrr,ARM::tADDrr,  0,             0,   0,    1,   0,  2,0, 1 },
     { ARM::t2ANDrr, 0,            ARM::tAND,     0,   0,    0,   1,  0,0, 0 },
@@ -469,6 +469,13 @@ Thumb2SizeReduce::ReduceSpecial(MachineBasicBlock &MBB, MachineInstr *MI,
       return true;
     return ReduceToNarrow(MBB, MI, Entry, LiveCPSR);
   }
+  case ARM::t2ADDrSPi: {
+    static const ReduceEntry NarrowEntry =
+      { ARM::t2ADDrSPi,ARM::tADDspi, 0, 7, 0, 1, 0, 1, 0, 1 };
+    if (MI->getOperand(0).getReg() == ARM::SP)
+      return ReduceToNarrow(MBB, MI, NarrowEntry, LiveCPSR);
+    return ReduceToNarrow(MBB, MI, Entry, LiveCPSR);
+  }
   }
   return false;
 }
diff --git a/test/CodeGen/Thumb2/2010-12-03-AddSPNarrowing.ll b/test/CodeGen/Thumb2/2010-12-03-AddSPNarrowing.ll
new file mode 100644
index 00000000000..5b91a5f65ae
--- /dev/null
+++ b/test/CodeGen/Thumb2/2010-12-03-AddSPNarrowing.ll
@@ -0,0 +1,11 @@
+; RUN: llc < %s -mtriple=thumbv7-apple-darwin | FileCheck %s
+; Radar 8724703: Make sure that a t2ADDrSPi instruction with SP as the
+; destination register is narrowed to tADDspi instead of tADDrSPi.
+
+define void @test() nounwind {
+entry:
+; CHECK: sub.w
+; CHECK: add.w
+  %Buffer.i = alloca [512 x i8], align 4
+  ret void
+}