[a64] Implement LStringCompareAndBranch

src/a64/lithium-a64.h

Index: src/a64/lithium-a64.h
diff --git a/src/a64/lithium-a64.h b/src/a64/lithium-a64.h
index be9423beb0c13c6959bc16d13738176e29d4d6f2..e6234f27f4aa17e81c02201e4b8bdbf97b3c76ae 100644
--- a/src/a64/lithium-a64.h
+++ b/src/a64/lithium-a64.h
@@ -173,6 +173,7 @@ class LCodeGen;
   V(StringAdd)                                  \
   V(StringCharCodeAt)                           \
   V(StringCharFromCode)                         \
+  V(StringCompareAndBranch)                     \
   V(StringLength)                               \
   V(SubI)                                       \
   V(TaggedToI)                                  \
@@ -2278,6 +2279,26 @@ class LStringCharFromCode: public LTemplateInstruction<1, 1, 0> {
 };
 
 
+class LStringCompareAndBranch: public LControlInstruction<2, 0> {
+ public:
+  LStringCompareAndBranch(LOperand* left, LOperand* right) {
+    inputs_[0] = left;
+    inputs_[1] = right;
+  }
+
+  LOperand* left() { return inputs_[0]; }
+  LOperand* right() { return inputs_[1]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(StringCompareAndBranch,
+                               "string-compare-and-branch")
+  DECLARE_HYDROGEN_ACCESSOR(StringCompareAndBranch)
+
+  Token::Value op() const { return hydrogen()->token(); }
+
+  virtual void PrintDataTo(StringStream* stream);
+};
+
+
 class LStringLength: public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LStringLength(LOperand* string) {