https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99561
Bug ID: 99561
Summary: gfortran reports an error for a truncation that is
permitted by the standard
Product: gcc
Version: 10.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: fortran
Assignee: unassigned at gcc dot gnu.org
Reporter: michal.paszta at mobica dot com
Target Milestone: ---
In this line of code:
INTEGER(KIND=1) :: var8 = 257_2
we try to cast an integer of kind 2 (16 bits) onto an integer of kind 1 (8
bits, value up to 256). This will result in a truncation of the value and is
allowed by the Fortran 2018 Standard, see Table 10.9, Fortran 2018 Standard.
$ ~/gcc/trunk/bin/gfortran issue.f90
issue.f90:17:27:
17 | INTEGER(KIND=1) :: var8 = 257_2
| 1
Error: Arithmetic overflow converting INTEGER(2) to INTEGER(1) at (1). This
check can be disabled with the option ‘-fno-range-check’
We believe the operation should be allowed. It could warn the programmer about
the truncation, but should not prevent a successful compilation.
The obvious workaround is to follow the suggestion for the error message and
add '-fno-range-check' - in that case I got no warning or error.
The report originates from a flang github issue:
https://github.com/flang-compiler/flang/issues/992 and was pointed out by Bryan
Chan.
I tried gfortran 7.5.0 and 10.2.0 and both acted the same.
