A64: Implement LMathFloorOfDiv and enable the instruction in hydrogen

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 7af082011b3f8f662ce6df3f39684285315adb35..cfb3adba0a745a25e957789179419abb4428520e 100644
--- a/src/a64/lithium-a64.h
+++ b/src/a64/lithium-a64.h
@@ -139,6 +139,7 @@ class LCodeGen;
   V(MathAbsTagged)                              \
   V(MathExp)                                    \
   V(MathFloor)                                  \
+  V(MathFloorOfDiv)                             \
   V(MathLog)                                    \
   V(MathMinMax)                                 \
   V(MathPowHalf)                                \
@@ -1833,6 +1834,25 @@ class LMathFloor: public LUnaryMathOperation<0> {
 };
 
 
+class LMathFloorOfDiv : public LTemplateInstruction<1, 2, 1> {
+ public:
+  LMathFloorOfDiv(LOperand* left,
+                  LOperand* right,
+                  LOperand* temp = NULL) {
+    inputs_[0] = left;
+    inputs_[1] = right;
+    temps_[0] = temp;
+  }
+
+  LOperand* left() { return inputs_[0]; }
+  LOperand* right() { return inputs_[1]; }
+  LOperand* temp() { return temps_[0]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(MathFloorOfDiv, "math-floor-of-div")
+  DECLARE_HYDROGEN_ACCESSOR(MathFloorOfDiv)
+};
+
+
 class LMathLog: public LUnaryMathOperation<0> {
  public:
   explicit LMathLog(LOperand* value) : LUnaryMathOperation<0>(value) { }