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

src/ia32/lithium-ia32.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 2323 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 SupportsMathFloorOfDiv() { return false; }

[fschneider, 2012/03/28 09:59:18]

I'd add those function only when we add this optimization to ia32. By using a
#ifdef in hydrogen-instructions.cc for the time being we can avoid adding unused
code to the other platforms.

[Alexandre, 2012/03/28 16:27:38]

Done.

+  static bool HasMagicNumberForDivisor(int32_t divisor) { return false; }
+  static HValue* SimplifiedDividendForMathFloorOfDiv(HValue* val) {
+    return NULL;
+  }
+  static HValue* SimplifiedDivisorForMathFloorOfDiv(HValue* val) {
+    return NULL;
+  }
+
  private:
   enum Status {
     UNUSED,
     BUILDING,
     DONE,
     ABORTED
   };
 
   LChunk* chunk() const { return chunk_; }
   CompilationInfo* info() const { return info_; }
@@ skipping 120 matching lines @@
 
   DISALLOW_COPY_AND_ASSIGN(LChunkBuilder);
 };
 
 #undef DECLARE_HYDROGEN_ACCESSOR
 #undef DECLARE_CONCRETE_INSTRUCTION
 
 } }  // namespace v8::internal
 
 #endif  // V8_IA32_LITHIUM_IA32_H_