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

src/arm/macro-assembler-arm.cc

 // 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 3692 matching lines @@
   b(ne, call_runtime);
 
   // Load the prototype from the map and loop if non-null.
   bind(&check_prototype);
   ldr(r1, FieldMemOperand(r2, Map::kPrototypeOffset));
   cmp(r1, null_value);
   b(ne, &next);
 }
 
 
-bool AreAliased(Register r1, Register r2, Register r3, Register r4) {
-  if (r1.is(r2)) return true;
-  if (r1.is(r3)) return true;
-  if (r1.is(r4)) return true;
-  if (r2.is(r3)) return true;
-  if (r2.is(r4)) return true;
-  if (r3.is(r4)) return true;
-  return false;
+#ifdef DEBUG
+bool AreAliased(Register reg1,
+                Register reg2,
+                Register reg3,
+                Register reg4,
+                Register reg5,
+                Register reg6) {
+  int n_of_valid_regs = reg1.is_valid() + reg2.is_valid() +
+    reg3.is_valid() + reg4.is_valid() + reg5.is_valid() + reg6.is_valid();
+
+  RegList regs = 0;
+  if (reg1.is_valid()) regs |= reg1.bit();
+  if (reg2.is_valid()) regs |= reg2.bit();
+  if (reg3.is_valid()) regs |= reg3.bit();
+  if (reg4.is_valid()) regs |= reg4.bit();
+  if (reg5.is_valid()) regs |= reg5.bit();
+  if (reg6.is_valid()) regs |= reg6.bit();
+  int n_of_non_aliasing_regs = NumRegs(regs);
+
+  return n_of_valid_regs != n_of_non_aliasing_regs;
 }
+#endif
 
 
 CodePatcher::CodePatcher(byte* address, int instructions)
     : address_(address),
       instructions_(instructions),
       size_(instructions * Assembler::kInstrSize),
       masm_(Isolate::Current(), address, size_ + Assembler::kGap) {
   // Create a new macro assembler pointing to the address of the code to patch.
   // The size is adjusted with kGap on order for the assembler to generate size
   // bytes of instructions without failing with buffer size constraints.
@@ skipping 24 matching lines @@
 void CodePatcher::EmitCondition(Condition cond) {
   Instr instr = Assembler::instr_at(masm_.pc_);
   instr = (instr & ~kCondMask) | cond;
   masm_.emit(instr);
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM