[turbofan] Fix invalid bounds check with overflowing offset.

src/compiler/x64/instruction-selector-x64.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 
 namespace v8 {
 namespace internal {
 namespace compiler {
@@ skipping 219 matching lines @@
       opcode = kCheckedLoadFloat64;
       break;
     default:
       UNREACHABLE();
       return;
   }
   if (offset->opcode() == IrOpcode::kInt32Add && CanCover(node, offset)) {
     Int32Matcher mlength(length);
     Int32BinopMatcher moffset(offset);
     if (mlength.HasValue() && moffset.right().HasValue() &&
+        moffset.right().Value() >= 0 &&
         mlength.Value() >= moffset.right().Value()) {
       Emit(opcode, g.DefineAsRegister(node), g.UseRegister(buffer),
            g.UseRegister(moffset.left().node()),
            g.UseImmediate(moffset.right().node()), g.UseImmediate(length));
       return;
     }
   }
   InstructionOperand* length_operand =
       g.CanBeImmediate(length) ? g.UseImmediate(length) : g.UseRegister(length);
   Emit(opcode, g.DefineAsRegister(node), g.UseRegister(buffer),
@@ skipping 28 matching lines @@
     default:
       UNREACHABLE();
       return;
   }
   InstructionOperand* value_operand =
       g.CanBeImmediate(value) ? g.UseImmediate(value) : g.UseRegister(value);
   if (offset->opcode() == IrOpcode::kInt32Add && CanCover(node, offset)) {
     Int32Matcher mlength(length);
     Int32BinopMatcher moffset(offset);
     if (mlength.HasValue() && moffset.right().HasValue() &&
+        moffset.right().Value() >= 0 &&
         mlength.Value() >= moffset.right().Value()) {
       Emit(opcode, nullptr, g.UseRegister(buffer),
            g.UseRegister(moffset.left().node()),
            g.UseImmediate(moffset.right().node()), g.UseImmediate(length),
            value_operand);
       return;
     }
   }
   InstructionOperand* length_operand =
       g.CanBeImmediate(length) ? g.UseImmediate(length) : g.UseRegister(length);
@@ skipping 1010 matching lines @@
            MachineOperatorBuilder::kFloat64Ceil |
            MachineOperatorBuilder::kFloat64RoundTruncate |
            MachineOperatorBuilder::kWord32ShiftIsSafe;
   }
   return MachineOperatorBuilder::kNoFlags;
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8