BoundsCheck should be extended to support array_bounds_checks_elimination

src/x64/lithium-codegen-x64.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 3471 matching lines @@
       case DICTIONARY_ELEMENTS:
       case NON_STRICT_ARGUMENTS_ELEMENTS:
         UNREACHABLE();
         break;
     }
   }
 }
 
 
 void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
-  if (instr->length()->IsRegister()) {
-    Register reg = ToRegister(instr->length());
+  int32_t lower_offset = instr->hydrogen()->lower_offset();
+  int32_t upper_offset = instr->hydrogen()->upper_offset();
+  LOperand* length = instr->length();
+  LOperand* index = instr->index();
+  if (instr->index()->IsConstantOperand()) {
+    int32_t c_index = ToInteger32(LConstantOperand::cast(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());
+    }
+    if (length->IsRegister()) {
+      if (FLAG_debug_code) {
+        __ AbortIfNotZeroExtended(ToRegister(length));
+      }
+      __ cmpl(ToRegister(length), Immediate(c_index + upper_offset));
+    } else {
+      __ cmpq(ToOperand(length), Immediate(c_index + upper_offset));
+    }
+    DeoptimizeIf(below_equal, instr->environment());
+  } else {
+    ASSERT(index->IsRegister());
+    Register reg_index = ToRegister(index);
     if (FLAG_debug_code) {
-      __ AbortIfNotZeroExtended(reg);
+      __ AbortIfNotZeroExtended(reg_index);
     }
-    if (instr->index()->IsConstantOperand()) {
-      __ cmpq(reg,
-              Immediate(ToInteger32(LConstantOperand::cast(instr->index()))));
+    if (lower_offset == 0 && upper_offset == 0) {
+      if (length->IsRegister()) {
+        if (FLAG_debug_code) {
+          __ AbortIfNotZeroExtended(ToRegister(length));
+        }
+        __ cmpl(ToRegister(length), ToRegister(index));
+      } else {
+        __ cmpq(ToOperand(length), ToRegister(index));
+      }
+      DeoptimizeIf(below_equal, instr->environment());
     } else {
-      Register reg2 = ToRegister(instr->index());
-      if (FLAG_debug_code) {
-        __ AbortIfNotZeroExtended(reg2);
+      ASSERT(instr->TempAt(0)->IsRegister());
+      Register temp_length = ToRegister(instr->TempAt(0));
+      if (length->IsRegister()) {
+        if (FLAG_debug_code) {
+          __ AbortIfNotZeroExtended(ToRegister(length));
+        }
+        __ movl(temp_length, ToRegister(length));
+      } else {
+        __ movq(temp_length, ToOperand(length));
       }
-      __ cmpq(reg, reg2);
-    }
-  } else {
-    if (instr->index()->IsConstantOperand()) {
-      __ cmpq(ToOperand(instr->length()),
-              Immediate(ToInteger32(LConstantOperand::cast(instr->index()))));
-    } else {
-      __ cmpq(ToOperand(instr->length()), ToRegister(instr->index()));
+      __ cmpl(reg_index, Immediate(-lower_offset));
+      DeoptimizeIf(less, instr->environment());
+      __ subl(temp_length, Immediate(upper_offset));
+      __ cmpl(reg_index, temp_length);
+      if (upper_offset >= 0) {
+        DeoptimizeIf(greater_equal, instr->environment());
+      } else {
+        DeoptimizeIf(above_equal, instr->environment());
+      }
     }
   }
-  DeoptimizeIf(below_equal, instr->environment());
 }
 
 
 void LCodeGen::DoStoreKeyedFastElement(LStoreKeyedFastElement* instr) {
   Register value = ToRegister(instr->value());
   Register elements = ToRegister(instr->object());
   Register key = instr->key()->IsRegister() ? ToRegister(instr->key()) : no_reg;
 
   Operand operand =
       BuildFastArrayOperand(instr->object(),
@@ skipping 1422 matching lines @@
                                FixedArray::kHeaderSize - kPointerSize));
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64