[Bug fortran/33002] New: 64-bit hexadecimal DATA incorrect

[Bug fortran/33002] New: 64-bit hexadecimal DATA incorrect

[sliwa at cft dot edu dot pl]

Statements like:

      DATA DMACH(1) / Z'0010000000000000' /
      DATA DMACH(2) / Z'7FEFFFFFFFFFFFFF' /
      DATA DMACH(3) / Z'3CA0000000000000' /
      DATA DMACH(4) / Z'3CB0000000000000' /
      DATA DMACH(5) / Z'3FD34413509F79FF' /

generate incorrect data.


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           Summary: 64-bit hexadecimal DATA incorrect
           Product: gcc
           Version: 4.2.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: sliwa at cft dot edu dot pl
 GCC build triplet: x86_64-redhat-linu
  GCC host triplet: x86_64-redhat-linu
GCC target triplet: x86_64-redhat-linu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33002

[Bug fortran/33002] 64-bit hexadecimal DATA incorrect

[sliwa at cft dot edu dot pl]

------- Comment #1 from sliwa at cft dot edu dot pl  2007-08-06 11:15 -------
Created an attachment (id=14029)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=14029&action=view)
sample source that demonstrates the problem

This is a SLATEC machine file


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33002

[Bug fortran/33002] 64-bit hexadecimal DATA incorrect

[sliwa at cft dot edu dot pl]

------- Comment #2 from sliwa at cft dot edu dot pl  2007-08-06 11:18 -------
There is also bug #33001. Both the bugs together make life difficult.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33002

[Bug fortran/33002] 64-bit hexadecimal DATA incorrect

[sliwa at cft dot edu dot pl]

------- Comment #3 from sliwa at cft dot edu dot pl  2007-08-06 11:21 -------
Now I see that 32-bit data is incorrect also.

      DATA RMACH(1) / Z'00800000' /
      DATA RMACH(2) / Z'7F7FFFFF' /
      DATA RMACH(3) / Z'33800000' /
      DATA RMACH(4) / Z'34000000' /
      DATA RMACH(5) / Z'3E9A209B' /


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33002

[Bug fortran/33002] Hexadecimal DATA incorrect

[burnus at gcc dot gnu dot org]

------- Comment #4 from burnus at gcc dot gnu dot org  2007-08-06 12:49 -------
Using
      REAL RMACH(5)
      DATA RMACH(1) / Z'00800000' /

is invalid Fortran 77/90/95/2003 as Fortran only allows:

"If a data-stmt-constant is a boz-literal-constant, the corresponding variable
shall be of type integer. The boz-literal-constant is treated as if it were an
int-literal-constant with a kind-param that specifies the representation method
with the largest decimal exponent range supported by the processor."

Gfortran interprets
      DATA RMACH(1) / Z'00800000' /
as
  rmach(1) = real(int(Z'00800000', maximallyNeededKind))
which is ok as the program is invalid and thus undfefined. Other compilers
interpret it as bit pattern. The result is are
8388608. respectively 1.1754944E-38.

Solution for Fortran 90/95/2003: Replace
  DATA RMACH(1) / Z'00800000' /
by
  RMACH(1) = transfer( Z'00800000', rmach)


I think nonetheless that gfortran misbehaves.
Expected:
- With -std=f95 etc. give a warning or an error
- With -std=gnu allow it (maybe with warning?) and tread as
  transfer(Z'...', 0.0) to be compatible with the other compilers.

NAG f95 gives always the error:
Error: Data-stmt-value incompatible with data-stmt-object

whereas, e.g., g95 and ifort give a warning for -std=f95 and have the same
result as with TRANSFER.

Warning (160): BOZ constant conversion at (1) is nonstandard
Warning: Fortran 95 does not allow boz constant in this context.


-- 

burnus at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |burnus at gcc dot gnu dot
                   |                            |org
  GCC build triplet|x86_64-redhat-linu          |
   GCC host triplet|x86_64-redhat-linu          |
 GCC target triplet|x86_64-redhat-linu          |
           Keywords|                            |diagnostic
            Summary|64-bit hexadecimal DATA     |Hexadecimal DATA incorrect
                   |incorrect                   |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33002

[Bug fortran/33002] Hexadecimal DATA incorrect

[kargl at gcc dot gnu dot org]

------- Comment #5 from kargl at gcc dot gnu dot org  2007-08-06 17:32 -------


*** This bug has been marked as a duplicate of 18026 ***


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kargl at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33002