[Bug c/35712] New: decimal float literal constant zero loses significant trailing zeroes

["janis at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>]

Decimal floating point types support significant trailing zeroes to
specify how much precision a value has.  Trailing zeroes are relevant
even for values of zero; for example, rounding 1.e-11dd to 10 places
after the decimal point results in 0.e-10dd.

The draft Technical Report N1241 for ISO/IEC TR 24732 doesn't specify
this directly, but section 9.5 "Formatted input/output specifiers"
shows expected output for five different representations of zero:
0, -0, 0.000000, 0e-07, and 0e+02.

Currently GCC converts all decimal float literal values of zero to
0.DF, 0.DD, or 0.DL.

I'm testing a patch to fix this but want a PR to record the issue.


-- 
           Summary: decimal float literal constant zero loses significant
                    trailing zeroes
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: janis at gcc dot gnu dot org
        ReportedBy: janis at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=35712