Fix issue 5275: The VM must always generate the most compact form of an integer (Smi, Mint or Bigin…

runtime/vm/bigint_operations.cc

 // Copyright 2012 Google Inc. All Rights Reserved.
 
 #include "vm/bigint_operations.h"
 
 #include "platform/utils.h"
 
 #include "vm/double_internals.h"
 #include "vm/exceptions.h"
 #include "vm/object_store.h"
 #include "vm/zone.h"
@@ skipping 646 matching lines @@
   uint64_t value = 0;
   for (int i = bigint.Length() - 1; i >= 0; i--) {
     value <<= kDigitBitSize;
     value += static_cast<intptr_t>(bigint.GetChunkAt(i));
   }
   return value;
 }
 
 
 int64_t BigintOperations::ToMint(const Bigint& bigint) {
+  if (bigint.IsZero()) {
+    return 0;
+  }
   ASSERT(FitsIntoMint(bigint));
   int64_t value = AbsToUint64(bigint);
   if (bigint.IsNegative()) {
     value = -value;
   }
   return value;
 }
 
 
 bool BigintOperations::AbsFitsIntoUint64(const Bigint& bigint) {
@@ skipping 985 matching lines @@
 int BigintOperations::CountBits(Chunk digit) {
   int result = 0;
   while (digit != 0) {
     digit >>= 1;
     result++;
   }
   return result;
 }
 
 }  // namespace dart