- Correctly handle negative constant indices when

runtime/vm/intermediate_language.cc

 // Copyright (c) 2013, 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 2293 matching lines @@
 
 bool CheckArrayBoundInstr::IsRedundant(RangeBoundary length) {
   // Check that array has an immutable length.
   if (!IsFixedLengthArrayType(array_type())) {
     return false;
   }
 
   Range* index_range = index()->definition()->range();
 
   // Range of the index is unknown can't decide if the check is redundant.
-  if (index_range == NULL) return false;
+  if (index_range == NULL) {
+    return false;
+  }
 
   // Range of the index is not positive. Check can't be redundant.
-  if (Range::ConstantMin(index_range).value() < 0) return false;
+  if (Range::ConstantMin(index_range).value() < 0) {
+    return false;
+  }
 
   RangeBoundary max = CanonicalizeBoundary(index_range->max(),
                                            RangeBoundary::OverflowedMaxSmi());
 
-  if (max.Overflowed()) return false;
+  if (max.Overflowed()) {
+    return false;
+  }
 
   // Try to compare constant boundaries.
   if (max.UpperBound().value() < length.LowerBound().value()) {
     return true;
   }
 
   length = CanonicalizeBoundary(length, RangeBoundary::OverflowedMaxSmi());
-  if (length.Overflowed()) return false;
+  if (length.Overflowed()) {
+    return false;
+  }
 
   // Try symbolic comparison.
   do {
     if (DependOnSameSymbol(max, length)) return max.offset() < length.offset();
   } while (CanonicalizeMaxBoundary(&max) || CanonicalizeMinBoundary(&length));
 
   // Failed to prove that maximum is bounded with array length.
   return false;
 }
 
@@ skipping 110 matching lines @@
     default:
       UNREACHABLE();
   }
   return kPowRuntimeEntry;
 }
 
 
 #undef __
 
 }  // namespace dart