[Bug fortran/54608] New: Wrong-code with SCAN and VERIFY

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54608

             Bug #: 54608
           Summary: Wrong-code with SCAN and VERIFY
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: burnus@gcc.gnu.org


Reported by James Van Buskirk in
https://groups.google.com/forum/?fromgroups=#!topic/comp.lang.fortran/5eAz5ns6AG0

Simplifing SCAN and VERIFY doesn't properly take the BACK= argument into
account if it is not constant. Solution: Do the same as for INDEX, namely:

--- a/gcc/fortran/simplify.c
+++ b/gcc/fortran/simplify.c
@@ -5249,3 +5249,4 @@ gfc_simplify_scan (gfc_expr *e, gfc_expr *c, gfc_expr *b,
gfc_expr *kind)

-  if (e->expr_type != EXPR_CONSTANT || c->expr_type != EXPR_CONSTANT)
+  if (e->expr_type != EXPR_CONSTANT || c->expr_type != EXPR_CONSTANT
+      || ( b != NULL && b->expr_type !=  EXPR_CONSTANT))
     return NULL;
@@ -6337,3 +6338,4 @@ gfc_simplify_verify (gfc_expr *s, gfc_expr *set, gfc_expr
*b, gfc_expr *kind)

-  if (s->expr_type != EXPR_CONSTANT || set->expr_type != EXPR_CONSTANT)
+  if (s->expr_type != EXPR_CONSTANT || set->expr_type != EXPR_CONSTANT
+      || ( b != NULL && b->expr_type !=  EXPR_CONSTANT))
     return NULL;


Test case (should print ".true."):

module m1
   implicit none
   contains
      subroutine s1(A)
         logical A
         integer iscan, iverify
         character(7), parameter :: tf(2) = ['.FALSE.','.TRUE. ']

         iscan = scan('AA','A',back=A)
         iverify = verify('xx','A',back=A)
         write(*,'(a)') 'SCAN test: A = '//trim(tf(iscan))
         write(*,'(a)') 'VERIFY test: A = '//trim(tf(iverify))
      end subroutine s1
end module m1

program p1
   use m1
   implicit none
   logical B

   B = .TRUE.
   call s1(B)
end program p1