Fix crash in modPow (issue 23693); various bigint knowledge missing.

runtime/vm/constant_propagator.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/constant_propagator.h"
 
 #include "vm/bit_vector.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
 #include "vm/flow_graph_range_analysis.h"
@@ skipping 490 matching lines @@
     case Token::kGT: return (result > 0);
     case Token::kLTE: return (result <= 0);
     case Token::kGTE: return (result >= 0);
     default:
       UNREACHABLE();
       return false;
   }
 }
 
 
+// Comparison instruction that is equivalent to the (left & right) == 0
+// comparison pattern.
 void ConstantPropagator::VisitTestSmi(TestSmiInstr* instr) {
   const Object& left = instr->left()->definition()->constant_value();
   const Object& right = instr->right()->definition()->constant_value();
   if (IsNonConstant(left) || IsNonConstant(right)) {
     SetValue(instr, non_constant_);
   } else if (IsConstant(left) && IsConstant(right)) {
-    if (left.IsInteger() && right.IsInteger()) {
+    // BitOp does not work on Bigints.
+    if (left.IsInteger() && right.IsInteger() &&
+        !left.IsBigint() && !right.IsBigint()) {
       const bool result = CompareIntegers(
           instr->kind(),
           Integer::Handle(I, Integer::Cast(left).BitOp(Token::kBIT_AND,
                                                        Integer::Cast(right))),
           Smi::Handle(I, Smi::New(0)));
       SetValue(instr, result ? Bool::True() : Bool::False());
     } else {
       SetValue(instr, non_constant_);
     }
   }
@@ skipping 1147 matching lines @@
   graph_->MergeBlocks();
   GrowableArray<BitVector*> dominance_frontier;
   graph_->ComputeDominators(&dominance_frontier);
 
   if (FLAG_trace_constant_propagation) {
     FlowGraphPrinter::PrintGraph("After CP", graph_);
   }
 }
 
 }  // namespace dart