Subzero ARM: lowerLoad and lowerStore.

Thought leaving "mov" simple and not handle memory operands,
but then we'd have to duplicate some of the lowerAssign code
for lowerLoad =/

BUG=  https://code.google.com/p/nativeclient/issues/detail?id=4076
R=kschimpf@google.com, stichnot@chromium.org

Review URL: https://codereview.chromium.org/1152703006

src/IceInstARM32.h

diff --git a/src/IceInstARM32.h b/src/IceInstARM32.h
index 9e0bb65..3f5f6bd 100644
--- a/src/IceInstARM32.h
+++ b/src/IceInstARM32.h
@@ -91,7 +91,7 @@
   // general Constant operands like ConstantRelocatable, since a relocatable
   // can potentially take up too many bits.
   static OperandARM32Mem *create(Cfg *Func, Type Ty, Variable *Base,
-                                 ConstantInteger32 *ImmOffset = nullptr,
+                                 ConstantInteger32 *ImmOffset,
                                  AddrMode Mode = Offset) {
     return new (Func->allocate<OperandARM32Mem>())
         OperandARM32Mem(Func, Ty, Base, ImmOffset, Mode);
@@ -277,6 +277,7 @@
     Push,
     Ret,
     Sbc,
+    Str,
     Sub,
     Umull
   };
@@ -763,6 +764,31 @@
   ~InstARM32Ret() override {}
 };
 
+// Store instruction. It's important for liveness that there is no Dest
+// operand (OperandARM32Mem instead of Dest Variable).
+class InstARM32Str : public InstARM32Pred {
+  InstARM32Str() = delete;
+  InstARM32Str(const InstARM32Str &) = delete;
+  InstARM32Str &operator=(const InstARM32Str &) = delete;
+
+public:
+  // Value must be a register.
+  static InstARM32Str *create(Cfg *Func, Variable *Value, OperandARM32Mem *Mem,
+                              CondARM32::Cond Predicate) {
+    return new (Func->allocate<InstARM32Str>())
+        InstARM32Str(Func, Value, Mem, Predicate);
+  }
+  void emit(const Cfg *Func) const override;
+  void emitIAS(const Cfg *Func) const override;
+  void dump(const Cfg *Func) const override;
+  static bool classof(const Inst *Inst) { return isClassof(Inst, Str); }
+
+private:
+  InstARM32Str(Cfg *Func, Variable *Value, OperandARM32Mem *Mem,
+               CondARM32::Cond Predicate);
+  ~InstARM32Str() override {}
+};
+
 // Unsigned Multiply Long: d.lo, d.hi := x * y
 class InstARM32Umull : public InstARM32Pred {
   InstARM32Umull() = delete;