MIPS: New array bounds check elimination pass (focused on induction variables and bitwise operation…

src/mips/lithium-codegen-mips.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 4145 matching lines @@
 
   // Name is always in a2.
   __ li(a2, Operand(instr->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,
+                            Register src1,
+                            const Operand& src2) {
+  if (FLAG_debug_code && check->hydrogen()->skip_check()) {
+    Label done;
+    __ Branch(&done, NegateCondition(cc), src1, src2);
+    __ stop("eliminated bounds check failed");
+    __ bind(&done);
+  } else {
+    DeoptimizeIf(cc, check->environment(), src1, src2);
+  }
+}
+
+
 void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
   if (instr->hydrogen()->skip_check()) return;
 
   Condition condition = instr->hydrogen()->allow_equality() ? hi : hs;
   if (instr->index()->IsConstantOperand()) {
     int constant_index =
         ToInteger32(LConstantOperand::cast(instr->index()));
     if (instr->hydrogen()->length()->representation().IsSmi()) {
       __ li(at, Operand(Smi::FromInt(constant_index)));
     } else {
       __ li(at, Operand(constant_index));
     }
-    DeoptimizeIf(condition,
-                 instr->environment(),
+    ApplyCheckIf(condition,
+                 instr,
                  at,
                  Operand(ToRegister(instr->length())));
   } else {
-    DeoptimizeIf(condition,
-                 instr->environment(),
+    ApplyCheckIf(condition,
+                 instr,
                  ToRegister(instr->index()),
                  Operand(ToRegister(instr->length())));
   }
 }
 
 
 void LCodeGen::DoStoreKeyedExternalArray(LStoreKeyed* instr) {
   Register external_pointer = ToRegister(instr->elements());
   Register key = no_reg;
   ElementsKind elements_kind = instr->elements_kind();
@@ skipping 1611 matching lines @@
   __ Subu(scratch, result, scratch);
   __ lw(result, FieldMemOperand(scratch,
                                 FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal