[v8-dev] Optimise Math.floor(x/y) to use integer division for specific divisor....

src/arm/lithium-arm.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 114 matching lines @@
   V(LoadFunctionPrototype)                      \
   V(LoadGlobalCell)                             \
   V(LoadGlobalGeneric)                          \
   V(LoadKeyedFastDoubleElement)                 \
   V(LoadKeyedFastElement)                       \
   V(LoadKeyedGeneric)                           \
   V(LoadKeyedSpecializedArrayElement)           \
   V(LoadNamedField)                             \
   V(LoadNamedFieldPolymorphic)                  \
   V(LoadNamedGeneric)                           \
+  V(MathFloorOfDiv)                             \
   V(ModI)                                       \
   V(MulI)                                       \
   V(NumberTagD)                                 \
   V(NumberTagI)                                 \
   V(NumberUntagD)                               \
   V(ObjectLiteral)                              \
   V(OsrEntry)                                   \
   V(OuterContext)                               \
   V(Parameter)                                  \
   V(Power)                                      \
@@ skipping 427 matching lines @@
   LDivI(LOperand* left, LOperand* right) {
     inputs_[0] = left;
     inputs_[1] = right;
   }
 
   DECLARE_CONCRETE_INSTRUCTION(DivI, "div-i")
   DECLARE_HYDROGEN_ACCESSOR(Div)
 };
 
 
+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;
+  }
+
+  DECLARE_CONCRETE_INSTRUCTION(MathFloorOfDiv, "math-floor-of-div")
+  DECLARE_HYDROGEN_ACCESSOR(MathFloorOfDiv)
+};
+
+
 class LMulI: public LTemplateInstruction<1, 2, 1> {
  public:
   LMulI(LOperand* left, LOperand* right, LOperand* temp) {
     inputs_[0] = left;
     inputs_[1] = right;
     temps_[0] = temp;
   }
 
   DECLARE_CONCRETE_INSTRUCTION(MulI, "mul-i")
   DECLARE_HYDROGEN_ACCESSOR(Mul)
@@ skipping 1688 matching lines @@
         pending_deoptimization_ast_id_(AstNode::kNoNumber) { }
 
   // Build the sequence for the graph.
   LChunk* Build();
 
   // Declare methods that deal with the individual node types.
 #define DECLARE_DO(type) LInstruction* Do##type(H##type* node);
   HYDROGEN_CONCRETE_INSTRUCTION_LIST(DECLARE_DO)
 #undef DECLARE_DO
 
+  static bool HasMagicNumberForDivisor(int32_t divisor);
+  static HValue* SimplifiedDividendForMathFloorOfDiv(HValue* val);
+  static HValue* SimplifiedDivisorForMathFloorOfDiv(HValue* val);
+
  private:
   enum Status {
     UNUSED,
     BUILDING,
     DONE,
     ABORTED
   };
 
   LChunk* chunk() const { return chunk_; }
   CompilationInfo* info() const { return info_; }
@@ skipping 116 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM_LITHIUM_ARM_H_