BoundsCheck should be extended to support array_bounds_checks_elimination

src/ia32/lithium-codegen-ia32.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 3539 matching lines @@
 
   __ mov(ecx, 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::DoBoundsCheck(LBoundsCheck* instr) {
+  int32_t lower_offset = instr->hydrogen()->lower_offset();
+  int32_t upper_offset = instr->hydrogen()->upper_offset();
   if (instr->index()->IsConstantOperand()) {
-    __ cmp(ToOperand(instr->length()),
-           Immediate(ToInteger32(LConstantOperand::cast(instr->index()))));
+    int32_t c_index = ToInteger32(LConstantOperand::cast(instr->index()));
+    int64_t upper_range = (int64_t)c_index + (int64_t)upper_offset;
+    if (c_index < -lower_offset || upper_range > ((int64_t)1 << 32)) {
+      DeoptimizeIf(no_condition, instr->environment());
+    }
+    __ cmp(ToOperand(instr->length()), Immediate(c_index + upper_offset));
     DeoptimizeIf(below_equal, instr->environment());
   } else {
-    __ cmp(ToRegister(instr->index()), ToOperand(instr->length()));
-    DeoptimizeIf(above_equal, instr->environment());
+    ASSERT(instr->index()->IsRegister());
+    Register reg_index = ToRegister(instr->index());
+    if (lower_offset == 0 && upper_offset == 0) {
+      __ cmp(reg_index, ToOperand(instr->length()));
+      DeoptimizeIf(above_equal, instr->environment());
+    } else {
+      Register temp_length = ToRegister(instr->TempAt(0));
+      __ mov(temp_length, ToOperand(instr->length()));
+      __ cmp(reg_index, Immediate(-lower_offset));
+      DeoptimizeIf(less, instr->environment());
+      __ sub(temp_length, Immediate(upper_offset));
+      __ cmp(reg_index, temp_length);
+      if (upper_offset >= 0) {
+        DeoptimizeIf(greater_equal, instr->environment());
+      } else {
+        DeoptimizeIf(above_equal, instr->environment());
+      }
+    }
   }
 }
 
 
 void LCodeGen::DoStoreKeyedSpecializedArrayElement(
     LStoreKeyedSpecializedArrayElement* instr) {
   ElementsKind elements_kind = instr->elements_kind();
   Operand operand(BuildFastArrayOperand(instr->external_pointer(),
                                         instr->key(),
                                         elements_kind,
@@ skipping 1652 matching lines @@
                               FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_IA32