[Bug c/48236] New: uint64_t and int64_t behave differently when converting to float

["juanval at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48236

           Summary: uint64_t and int64_t behave differently when
                    converting to float
           Product: gcc
           Version: 4.4.5
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: juanval@gmail.com


Created attachment 23749
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23749
Small code to show uint64_t / int64_t difference

Attached code shows a comparison of converted int->float values:
( (float)(ui+1) != ((float)ui) + 1.f )

This comparison fails beginning at number 16777216 for ui of type uint64_t, but
it doesn't fail there for ui of type int64_t.

Tested in gcc version 4.4.5 (Ubuntu/Linaro 4.4.4-14ubuntu5), Ubuntu 10.10 32
bits, atom processor. 

Compiled with no parameters: gcc test.c && ./a.out

Tested also in mingw 4.4.5, same problem.

Tested in MSVC (vs2010) too, and it doesn't fail early for uint64_t, like gcc
does.