id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
8700,multiprecision : Trying to cast to unsigned from cpp_int > 19 bits causes crash,danq@…,John Maddock,"The code segment below shows an iteration through a list of fields.  Each field will be filled with a sub-set of the cpp_int number.

If the cpp_int number is 20-bits or larger, the second line of the 'for' loop (where the cast to unsigned occurs) crashes bit-time.

When I comment out the cast, the code works file.  If I reduce the size of the cpp_int 'i_addr' to 19 bits or less, it works fine.

20 bits or more causes a complete crash.

Ticket #8423 comments about a similar crash and that it was fixed for the next release.  I was unable to find the fix.  Note that in that example, the 32-bit value crashes while the 16-bit one does not.

Very similar to my case, so I suspect it is the same bug.

Can someone please confirm this?



Mingw 10.2 -
GCC 4.8.1 - Boost 1.53.0 - FreeType 2.4.12, libogg 1.3.1, PCRE 8.33, pngcrush 1.7.60.


//-----------------------------------------------------------//

typedef boost :: multiprecision :: cpp_int Bit_Reg ;

Bit_Reg i_addr ;    // This is incremented elsewhere, but used in this loop

for (auto * i_field : table->i_field_list) 
{ 
  Bit_Reg i_value = i_addr >> i_field->bits.lsb ;

  i_field->value  = i_value.template convert_to <unsigned> () ;
}
",Bugs,closed,To Be Determined,multiprecision,Boost 1.53.0,Showstopper,invalid,crash cast multiprecision dump,