Fix double-rounding in strtod.

test/cctest/test-strtod.cc

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 
 #include <stdlib.h>
 
 #include "v8.h"
 
 #include "cctest.h"
 #include "strtod.h"
 
 using namespace v8::internal;
@@ skipping 180 matching lines @@
   CHECK_EQ(1234e305, StrtodChar("123400000", 300));
   CHECK_EQ(1234e304, StrtodChar("123400000", 299));
   CHECK_EQ(V8_INFINITY, StrtodChar("180000000", 300));
   CHECK_EQ(17e307, StrtodChar("170000000", 300));
   CHECK_EQ(V8_INFINITY, StrtodChar("00000001000000", 303));
   CHECK_EQ(1e308, StrtodChar("000000000000100000", 303));
   CHECK_EQ(1234e305, StrtodChar("00000000123400000", 300));
   CHECK_EQ(1234e304, StrtodChar("0000000123400000", 299));
   CHECK_EQ(V8_INFINITY, StrtodChar("00000000180000000", 300));
   CHECK_EQ(17e307, StrtodChar("00000000170000000", 300));
+
+  // The following number is the result of 89255.0/1e-22. Both floating-point
+  // numbers can be accurately represented with doubles. However on Linux,x86
+  // the floating-point stack is set to 80bits and the double-rounding
+  // introduces an error.
+  CHECK_EQ(89255e-22, StrtodChar("89255", -22));
 }