New array bounds check elimination pass (focused on induction variables and bitwise operations).

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 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 4054 matching lines @@
   ASSERT(ToRegister(instr->value()).is(rax));
 
   __ Move(rcx, instr->hydrogen()->name());
   Handle<Code> ic = (instr->strict_mode_flag() == kStrictMode)
       ? isolate()->builtins()->StoreIC_Initialize_Strict()
       : isolate()->builtins()->StoreIC_Initialize();
   CallCode(ic, RelocInfo::CODE_TARGET, instr);
 }
 
 
+void LCodeGen::ApplyCheckIf(Condition cc, LBoundsCheck* check) {
+  if (FLAG_debug_code && check->hydrogen()->skip_check()) {
+    Label done;
+    __ j(NegateCondition(cc), &done, Label::kNear);
+    __ int3();
+    __ bind(&done);
+  } else {
+    DeoptimizeIf(cc, check->environment());
+  }
+}
+
+
 void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
   if (instr->hydrogen()->skip_check()) return;
 
   if (instr->length()->IsRegister()) {
     Register reg = ToRegister(instr->length());
     if (!instr->hydrogen()->length()->representation().IsSmi()) {
       __ AssertZeroExtended(reg);
     }
     if (instr->index()->IsConstantOperand()) {
       int constant_index =
@@ skipping 17 matching lines @@
           ToInteger32(LConstantOperand::cast(instr->index()));
       if (instr->hydrogen()->length()->representation().IsSmi()) {
         __ Cmp(length, Smi::FromInt(constant_index));
       } else {
         __ cmpq(length, Immediate(constant_index));
       }
     } else {
       __ cmpq(length, ToRegister(instr->index()));
     }
   }
-  DeoptimizeIf(below_equal, instr->environment());
+  Condition condition =
+      instr->hydrogen()->allow_equality() ? below : below_equal;
+  ApplyCheckIf(condition, instr);
 }
 
 
 void LCodeGen::DoStoreKeyedExternalArray(LStoreKeyed* instr) {
   ElementsKind elements_kind = instr->elements_kind();
   LOperand* key = instr->key();
   if (!key->IsConstantOperand()) {
     Register key_reg = ToRegister(key);
     // Even though the HLoad/StoreKeyedFastElement instructions force
     // the input representation for the key to be an integer, the input
@@ skipping 1482 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64