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

src/x64/lithium-codegen-x64.cc

Index: src/x64/lithium-codegen-x64.cc
diff --git a/src/x64/lithium-codegen-x64.cc b/src/x64/lithium-codegen-x64.cc
index beaa1f1df96853c515d0c47c7a88ad3380edaacd..1813bbb7f1ab1a8f748a03c014cd977c1a2c424f 100644
--- a/src/x64/lithium-codegen-x64.cc
+++ b/src/x64/lithium-codegen-x64.cc
@@ -4072,6 +4072,18 @@ void LCodeGen::DoStoreNamedGeneric(LStoreNamedGeneric* 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;
 
@@ -4109,7 +4121,9 @@ void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
       __ cmpq(length, ToRegister(instr->index()));
     }
   }
-  DeoptimizeIf(below_equal, instr->environment());
+  Condition condition =
+      instr->hydrogen()->allow_equality() ? below : below_equal;
+  ApplyCheckIf(condition, instr);
 }