[flang] Runtime failure with stream formatted I/O

[DanielCChen]

Consider the following code

program main
use ieee_arithmetic

    complex(4), pointer :: cx1(:,:), cx2(:)
    character(:), allocatable :: string

10  format(dc, 12(" (", e22.15, " ; ", e22.15, " );"))

    open (1, file='valueSeparator005.data', access='stream', form='formatted')

    string = repeat(' ', 800)

    allocate (cx1(2,5))

    cx1 = cmplx(reshape((/(i, i=-10,-1)/), (/2,5/)), &
        reshape((/(i**2, i=-10,-1)/), (/2,5/)), 4)

    write (string, 10) cx1

    !! now read in data from both external and internal files
    allocate (cx2(10))

    read (string, *, decimal='coMMA') cx2
end

Flang failed at the runtime with

> a.out

fatal Fortran runtime error(t.f:23): Bad real input data at column 51 of record 1
IOT/Abort trap(coredump)

All ifort, gfortran and XLF compile and execute the program successfully.

[llvmbot]

@llvm/issue-subscribers-flang-runtime

Author: Daniel Chen (DanielCChen)

Details

Consider the following code ``` program main use ieee_arithmetic

complex(4), pointer :: cx1(:,:), cx2(:)
character(:), allocatable :: string

10 format(dc, 12(" (", e22.15, " ; ", e22.15, " );"))

open (1, file='valueSeparator005.data', access='stream', form='formatted')

string = repeat(' ', 800)

allocate (cx1(2,5))

cx1 = cmplx(reshape((/(i, i=-10,-1)/), (/2,5/)), &
    reshape((/(i**2, i=-10,-1)/), (/2,5/)), 4)

write (string, 10) cx1

!! now read in data from both external and internal files
allocate (cx2(10))

read (string, *, decimal='coMMA') cx2

end

Flang failed at the runtime with

> a.out

fatal Fortran runtime error(t.f:23): Bad real input data at column 51 of record 1
IOT/Abort trap(coredump)

All ifort, gfortran and XLF compile and execute the program successfully.
</details>

[klausler]

The use of stream I/O on unit 1 seems to affect only the OPEN statement. All of the I/O afterwards is internal.

[klausler]

Reduced case:

complex z(2)
character(20) :: str = "(0,;1, );(2,;3,)"
read(str,*,decimal='comma') z
print *, z
end