Fortran: Fix checking for IMPURE in DO CONCURRENT.

	PR fortran/119836

gcc/fortran/ChangeLog:

	* resolve.cc (check_pure_function): Fix checking for
	an impure subprogram within a DO CONCURRENT construct.
	(pure_subroutine): Ditto.

gcc/testsuite/ChangeLog:

	* gfortran.dg/do_concurrent_all_clauses.f90: Remove invalid
	dg-error test.
	* gfortran.dg/pr119836_1.f90: New test.
	* gfortran.dg/pr119836_2.f90: New test.
	* gfortran.dg/pr119836_3.f90: New test.
	* gfortran.dg/pr119836_4.f90: New test.

1 files changed, 39 insertions, 10 deletions

diff --git a/gcc/fortran/resolve.cc b/gcc/fortran/resolve.cc
index 2ecbd50..f03708e 100644
--- a/gcc/fortran/resolve.cc
+++ b/gcc/fortran/resolve.cc
@@ -3260,14 +3260,30 @@ static bool check_pure_function (gfc_expr *e)
      gfc_do_concurrent_flag = 0 when the check for an impure function
      occurs.  Check the stack to see if the source code has a nested
      BLOCK construct.  */
+
   for (stack = cs_base; stack; stack = stack->prev)
     {
-      if (stack->current->op == EXEC_BLOCK) saw_block = true;
+      if (!saw_block && stack->current->op == EXEC_BLOCK)
+	{
+	  saw_block = true;
+	  continue;
+	}
+
       if (saw_block && stack->current->op == EXEC_DO_CONCURRENT)
 	{
-	  gfc_error ("Reference to impure function at %L inside a "
-		     "DO CONCURRENT", &e->where);
-	  return false;
+	  bool is_pure;
+	  is_pure = (e->value.function.isym
+		     && (e->value.function.isym->pure
+			 || e->value.function.isym->elemental))
+		    || (e->value.function.esym
+			&& (e->value.function.esym->attr.pure
+			    || e->value.function.esym->attr.elemental));
+	  if (!is_pure)
+	    {
+	      gfc_error ("Reference to impure function at %L inside a "
+			 "DO CONCURRENT", &e->where);
+	      return false;
+	    }
 	}
     }
 
@@ -3663,16 +3679,29 @@ pure_subroutine (gfc_symbol *sym, const char *name, locus *loc)
 
   /* A BLOCK construct within a DO CONCURRENT construct leads to
      gfc_do_concurrent_flag = 0 when the check for an impure subroutine
-     occurs.  Check the stack to see if the source code has a nested
-     BLOCK construct.  */
+     occurs.  Walk up the stack to see if the source code has a nested
+     construct.  */
+
   for (stack = cs_base; stack; stack = stack->prev)
     {
-      if (stack->current->op == EXEC_BLOCK) saw_block = true;
+      if (stack->current->op == EXEC_BLOCK)
+	{
+	  saw_block = true;
+	  continue;
+	}
+
       if (saw_block && stack->current->op == EXEC_DO_CONCURRENT)
 	{
-	  gfc_error ("Subroutine call at %L in a DO CONCURRENT block "
-		     "is not PURE", loc);
-	  return false;
+
+	  bool is_pure = true;
+	  is_pure = sym->attr.pure || sym->attr.elemental;
+
+	  if (!is_pure)
+	    {
+	      gfc_error ("Subroutine call at %L in a DO CONCURRENT block "
+			 "is not PURE", loc);
+	      return false;
+	    }
 	}
     }