Fortran: fix memleak for character,value dummy of bind(c) procedure [PR110360]

Testcase gfortran.dg/bind_c_usage_13.f03 exhibited a memleak in the frontend
occuring when passing a character literal to a character,value dummy of a
bind(c) procedure, due to a missing cleanup in the conversion of the actual
argument expression.  Reduced testcase:

  program p
    interface
       subroutine val_c (c) bind(c)
         use iso_c_binding, only: c_char
         character(len=1,kind=c_char), value :: c
       end subroutine val_c
    end interface
    call val_c ("A")
  end

gcc/fortran/ChangeLog:

	PR fortran/110360
	* trans-expr.cc (conv_scalar_char_value): Use gfc_replace_expr to
	avoid leaking replaced gfc_expr.

1 files changed, 3 insertions, 2 deletions

diff --git a/gcc/fortran/trans-expr.cc b/gcc/fortran/trans-expr.cc
index 52cd88f..6e9e76c 100644
--- a/gcc/fortran/trans-expr.cc
+++ b/gcc/fortran/trans-expr.cc
@@ -4044,8 +4044,9 @@ conv_scalar_char_value (gfc_symbol *sym, gfc_se *se, gfc_expr **expr)
       gfc_typespec ts;
       gfc_clear_ts (&ts);
 
-      *expr = gfc_get_int_expr (gfc_default_character_kind, NULL,
-				(*expr)->value.character.string[0]);
+      gfc_expr *tmp = gfc_get_int_expr (gfc_default_character_kind, NULL,
+					(*expr)->value.character.string[0]);
+      gfc_replace_expr (*expr, tmp);
     }
   else if (se != NULL && (*expr)->expr_type == EXPR_VARIABLE)
     {