From 84cccff60a978174271a30042bf7841d2ae436eb Mon Sep 17 00:00:00 2001
From: Harald Anlauf <anlauf@gmx.de>
Date: Fri, 24 Sep 2021 19:10:15 +0200
Subject: [PATCH] Fortran - improve checking for intrinsics allowed in constant
 expressions

gcc/fortran/ChangeLog:

	PR fortran/102458
	* expr.c (is_non_constant_intrinsic): Check for intrinsics
	excluded in constant expressions (F2018:10.1.2).
	(gfc_is_constant_expr): Use that check.

gcc/testsuite/ChangeLog:

	PR fortran/102458
	* gfortran.dg/pr102458.f90: New test.
---
 gcc/fortran/expr.c                     | 32 ++++++++++++++++++++++++++
 gcc/testsuite/gfortran.dg/pr102458.f90 | 42 ++++++++++++++++++++++++++++++++++
 2 files changed, 74 insertions(+)
 create mode 100644 gcc/testsuite/gfortran.dg/pr102458.f90

diff --git a/gcc/fortran/expr.c b/gcc/fortran/expr.c
index 604e63e..5ad1c4f 100644
--- a/gcc/fortran/expr.c
+++ b/gcc/fortran/expr.c
@@ -990,6 +990,34 @@ done:
 }
 
 
+/* Standard intrinsics listed under F2018:10.1.2 (6), which are excluded in
+   constant expressions, except TRANSFER (c.f. item (8)), which would need
+   separate treatment.  */
+
+static bool
+is_non_constant_intrinsic (gfc_expr *e)
+{
+  if (e->expr_type == EXPR_FUNCTION
+      && e->value.function.isym)
+    {
+      switch (e->value.function.isym->id)
+	{
+	  case GFC_ISYM_COMMAND_ARGUMENT_COUNT:
+	  case GFC_ISYM_GET_TEAM:
+	  case GFC_ISYM_NULL:
+	  case GFC_ISYM_NUM_IMAGES:
+	  case GFC_ISYM_TEAM_NUMBER:
+	  case GFC_ISYM_THIS_IMAGE:
+	    return true;
+
+	default:
+	  return false;
+	}
+    }
+  return false;
+}
+
+
 /* Determine if an expression is constant in the sense of F08:7.1.12.
  * This function expects that the expression has already been simplified.  */
 
@@ -1023,6 +1051,10 @@ gfc_is_constant_expr (gfc_expr *e)
       gcc_assert (e->symtree || e->value.function.esym
 		  || e->value.function.isym);
 
+      /* Check for intrinsics excluded in constant expressions.  */
+      if (e->value.function.isym && is_non_constant_intrinsic (e))
+	return false;
+
       /* Call to intrinsic with at least one argument.  */
       if (e->value.function.isym && e->value.function.actual)
 	{
diff --git a/gcc/testsuite/gfortran.dg/pr102458.f90 b/gcc/testsuite/gfortran.dg/pr102458.f90
new file mode 100644
index 0000000..555e497
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr102458.f90
@@ -0,0 +1,42 @@
+! { dg-do compile }
+! { dg-options "-fcoarray=lib" }
+! PR fortran/102458 - standard intrinsics excluded in constant expressions
+
+subroutine s1
+  integer :: a(command_argument_count()) = 1 ! { dg-error "Automatic array" }
+  print *, a
+end
+
+program p
+  block
+    integer :: a(get_team()) = 1 ! { dg-error "Automatic array" }
+    print *, a
+  end block
+end
+
+subroutine s2
+  integer :: a(num_images()) = 1 ! { dg-error "Automatic array" }
+  print *, a
+end
+
+function f()
+  block
+    integer :: a(team_number()) = 0 ! { dg-error "Automatic array" }
+    a = 1
+  end block
+end
+
+subroutine s3
+  integer :: a(this_image()) = 1 ! { dg-error "Automatic array" }
+  print *, a
+end
+
+subroutine s4
+  integer, parameter :: n = 4
+  integer, parameter :: x(transfer(n, n)) = 1 ! legal
+  integer            :: y(transfer(n, n)) = 2 ! legal
+  integer, parameter :: k = size (x)          ! ok
+! integer, parameter :: m = size (y)          ! fails, tracked separately
+  print *, k, x, y
+  if (k /= size (y)) stop 1
+end
-- 
2.7.4