https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80467
Bug ID: 80467
Summary: Function Without Arguments Fails to Generate Error
When Declared Later
Product: gcc
Version: 6.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: jeffrey.armstrong at approximatrix dot com
Target Milestone: ---
Calling a real-valued function without arguments and without providing an
argument list will generate unexpected results if the function is declared
after its call. Consider the following short example:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
program noargs
implicit none
Print *, "Testing..."
Call TestArgs
Print *, "Done."
contains
Subroutine TestArgs
implicit none
Real::compareTo
Integer::i
compareTo = GetValue
do i=1,10
if(compareTo < Real(i)) Then
Print *, "bigger"
end if
end do
End Subroutine TestArgs
Function GetValue()
implicit none
Real::GetValue
GetValue = 3.0
End Function GetValue
end program noargs
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
6.3.0 will compile the above without any error messages, but the value of
"compareTo" in the subroutine "TestArgs" will be a nonsense value. If the
function GetValue is defined prior to TestArgs, the compiler correctly
generates the error stating the GetValue requires an argument list.
In a far more complex program, this same scenario was causing an ICE at
gcc/expr.c:268. Either adding an empty argument list or rearranging the order
of the function and calling subroutine fixed the issue.
This bug was seen on MinGW-w64 and macOS (x64), but it should occur anywhere.
