[crankshaft] Fragmentation-free allocation folding.

src/crankshaft/arm64/lithium-arm64.h

Index: src/crankshaft/arm64/lithium-arm64.h
diff --git a/src/crankshaft/arm64/lithium-arm64.h b/src/crankshaft/arm64/lithium-arm64.h
index 237487ff884d6ef284ab1ebf38de7efa80e4e90b..eed2489b47f052201c42b584d6cfcb0115f80b26 100644
--- a/src/crankshaft/arm64/lithium-arm64.h
+++ b/src/crankshaft/arm64/lithium-arm64.h
@@ -70,6 +70,7 @@ class LCodeGen;
   V(Drop)                                    \
   V(Dummy)                                   \
   V(DummyUse)                                \
+  V(FastAllocate)                            \
   V(FlooringDivByConstI)                     \
   V(FlooringDivByPowerOf2I)                  \
   V(FlooringDivI)                            \
@@ -163,7 +164,6 @@ class LCodeGen;
   V(UnknownOSRValue)                         \
   V(WrapReceiver)
 
-
 #define DECLARE_CONCRETE_INSTRUCTION(type, mnemonic)            \
   Opcode opcode() const final { return LInstruction::k##type; } \
   void CompileToNative(LCodeGen* generator) final;              \
@@ -626,6 +626,21 @@ class LAllocate final : public LTemplateInstruction<1, 2, 3> {
   DECLARE_HYDROGEN_ACCESSOR(Allocate)
 };
 
+class LFastAllocate final : public LTemplateInstruction<1, 1, 2> {
+ public:
+  LFastAllocate(LOperand* size, LOperand* temp1, LOperand* temp2) {
+    inputs_[0] = size;
+    temps_[0] = temp1;
+    temps_[1] = temp2;
+  }
+
+  LOperand* size() { return inputs_[0]; }
+  LOperand* temp1() { return temps_[0]; }
+  LOperand* temp2() { return temps_[1]; }
+
+  DECLARE_CONCRETE_INSTRUCTION(FastAllocate, "fast-allocate")
+  DECLARE_HYDROGEN_ACCESSOR(Allocate)
+};
 
 class LApplyArguments final : public LTemplateInstruction<1, 4, 0> {
  public: