1 files changed, 74 insertions, 0 deletions
diff --git a/gcc/testsuite/gfortran.dg/string_length_1.f90 b/gcc/testsuite/gfortran.dg/string_length_1.f90
new file mode 100644
index 000000000..50883f010
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/string_length_1.f90
@@ -0,0 +1,74 @@
+! { dg-do run }
+! Testcase for PR 31203
+! We used to create strings with negative length
+subroutine foo(i)
+  integer :: i
+  character(len=i) :: s(2)
+  if (len(s) < 0) call abort
+  if (len(s) /= max(i,0)) call abort
+end
+
+function gee(i)
+  integer, intent(in) :: i
+  character(len=i) :: gee
+
+  gee = ""
+end function gee
+
+subroutine s1(i,j)
+  character(len=i-j) :: a
+  if (len(a) < 0) call abort()
+end subroutine
+
+program test
+  interface
+    function gee(i)
+      integer, intent(in) :: i
+      character(len=i) :: gee
+    end function gee
+  end interface
+
+  call foo(2)
+  call foo(-1)
+  call s1(1,2)
+  call s1(-1,-8)
+  call s1(-8,-1)
+
+  if (len(gee(2)) /= 2) call abort
+  if (len(gee(-5)) /= 0) call abort
+  if (len(gee(intfunc(3))) /= max(intfunc(3),0)) call abort
+  if (len(gee(intfunc(2))) /= max(intfunc(2),0)) call abort
+
+  if (len(bar(2)) /= 2) call abort
+  if (len(bar(-5)) /= 0) call abort
+  if (len(bar(intfunc(3))) /= max(intfunc(3),0)) call abort
+  if (len(bar(intfunc(2))) /= max(intfunc(2),0)) call abort
+
+  if (cow(bar(2)) /= 2) call abort
+  if (cow(bar(-5)) /= 0) call abort
+  if (cow(bar(intfunc(3))) /= max(intfunc(3),0)) call abort
+  if (cow(bar(intfunc(2))) /= max(intfunc(2),0)) call abort
+
+contains
+
+  function bar(i)
+    integer, intent(in) :: i
+    character(len=i) :: bar
+  
+    bar = ""
+  end function bar
+
+  function cow(c)
+    character(len=*), intent(in) :: c
+    integer :: cow
+    cow = len(c)
+  end function cow
+
+  pure function intfunc(i)
+    integer, intent(in) :: i
+    integer :: intfunc
+
+    intfunc = 2*i-5
+  end function intfunc
+
+end program test