Fix reintroduction of global variables that have been deleted.

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index 5e2e380ba8927688a9b2b4e11b58652991694b39..50da6497208502bcf9fa16e9d56bb503db7b18b2 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -2195,8 +2195,22 @@ void LCodeGen::DoLoadGlobal(LLoadGlobal* instr) {
 
 void LCodeGen::DoStoreGlobal(LStoreGlobal* instr) {
   Register value = ToRegister(instr->InputAt(0));
-  __ mov(ip, Operand(Handle<Object>(instr->hydrogen()->cell())));
-  __ str(value, FieldMemOperand(ip, JSGlobalPropertyCell::kValueOffset));
+  Register scratch = ToRegister(instr->TempAt(0));
+  Register scratch2 = scratch0();
+
+  // If the cell we are storing to contains the hole it could have
+  // been deleted from the property dictionary. In that case, we need
+  // to update the property details in the property dictionary to mark
+  // it as no longer deleted. We deoptimize in that case.
+  __ mov(scratch, Operand(Handle<Object>(instr->hydrogen()->cell())));
+  __ ldr(scratch2,
+         FieldMemOperand(scratch, JSGlobalPropertyCell::kValueOffset));
+  __ LoadRoot(ip, Heap::kTheHoleValueRootIndex);
+  __ cmp(scratch2, ip);
+  DeoptimizeIf(eq, instr->environment());
+
+  // Store the value.
+  __ str(value, FieldMemOperand(scratch, JSGlobalPropertyCell::kValueOffset));
 }