Ensure that LowerBound and UpperBound return overflow marker when overflow occurs.

runtime/vm/intermediate_language.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/intermediate_language.h"
 
 #include "vm/bit_vector.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_allocator.h"
 #include "vm/flow_graph_builder.h"
@@ skipping 2140 matching lines @@
     return FromConstant(Smi::Cast(defn->AsConstant()->value()).Value() + offs);
   }
   return RangeBoundary(kSymbol, reinterpret_cast<intptr_t>(defn), offs);
 }
 
 
 RangeBoundary RangeBoundary::LowerBound() const {
   if (IsConstant()) return *this;
   return Add(Range::ConstantMin(symbol()->range()),
              RangeBoundary::FromConstant(offset_),
-             MinSmi());
+             OverflowedMinSmi());
 }
 
 
 RangeBoundary RangeBoundary::UpperBound() const {
   if (IsConstant()) return *this;
   return Add(Range::ConstantMax(symbol()->range()),
              RangeBoundary::FromConstant(offset_),
-             MaxSmi());
+             OverflowedMaxSmi());
 }
 
 
 static Definition* UnwrapConstraint(Definition* defn) {
   while (defn->IsConstraint()) {
     defn = defn->AsConstraint()->value()->definition();
   }
   return defn;
 }
 
@@ skipping 129 matching lines @@
 
   return true;
 }
 
 
 RangeBoundary RangeBoundary::Min(RangeBoundary a, RangeBoundary b) {
   if (DependOnSameSymbol(a, b)) {
     return (a.offset() <= b.offset()) ? a : b;
   }
 
-  const intptr_t min_a = a.LowerBound().value();
-  const intptr_t min_b = b.LowerBound().value();
+  const intptr_t min_a = a.LowerBound().Clamp().value();
+  const intptr_t min_b = b.LowerBound().Clamp().value();
 
   return RangeBoundary::FromConstant(Utils::Minimum(min_a, min_b));
 }
 
 
 RangeBoundary RangeBoundary::Max(RangeBoundary a, RangeBoundary b) {
   if (DependOnSameSymbol(a, b)) {
     return (a.offset() >= b.offset()) ? a : b;
   }
 
-  const intptr_t max_a = a.UpperBound().value();
-  const intptr_t max_b = b.UpperBound().value();
+  const intptr_t max_a = a.UpperBound().Clamp().value();
+  const intptr_t max_b = b.UpperBound().Clamp().value();
 
   return RangeBoundary::FromConstant(Utils::Maximum(max_a, max_b));
 }
 
 
 void Definition::InferRange() {
   ASSERT(GetPropagatedCid() == kSmiCid);  // Has meaning only for smis.
   if (range_ == NULL) {
     range_ = Range::Unknown();
   }
@@ skipping 367 matching lines @@
     default:
       UNREACHABLE();
       return -1;
   }
 }
 
 
 #undef __
 
 }  // namespace dart