[strong] Disallow implicit conversions for comparison

src/compiler/js-typed-lowering.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/code-factory.h"
 #include "src/compiler/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/node-matchers.h"
@@ skipping 452 matching lines @@
         break;
       case IrOpcode::kJSGreaterThanOrEqual:
         stringOp = simplified()->StringLessThanOrEqual();
         r.SwapInputs();  // a >= b => b <= a
         break;
       default:
         return NoChange();
     }
     return r.ChangeToPureOperator(stringOp);
   }
+  if (r.IsStrong() && !r.BothInputsAre(Type::Number())) {
+    return NoChange();
+  }
 #if 0
   // TODO(turbofan): General ToNumber disabled for now because:
   //   a) The inserted ToNumber operation screws up observability of valueOf.
   //   b) Deoptimization at ToNumber doesn't have corresponding bailout id.
   Type* maybe_string = Type::Union(Type::String(), Type::Receiver(), zone());
   if (r.OneInputCannotBe(maybe_string)) {
     // If one input cannot be a string, then emit a number comparison.
     ...
   }
 #endif
@@ skipping 827 matching lines @@
 }
 
 
 MachineOperatorBuilder* JSTypedLowering::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8