PR fortran/95503 - Fix ICE in gfc_is_simply_contiguous, at fortran/expr.c:5844

The check for assigning a pointer that cannot be determined to be simply
contiguous at compile time to a contiguous pointer does not need to be
invoked if the lhs of the assignment is known to have conflicting attributes.

2020-06-11  Harald Anlauf  <anlauf@gmx.de>

gcc/fortran/
	PR fortran/95503
	* expr.c (gfc_check_pointer_assign): Skip contiguity check of rhs
	of pointer assignment if lhs cannot be simply contiguous.

gcc/testsuite/
	PR fortran/95503
	* gfortran.dg/pr95503.f90: New test.

(cherry picked from commit 87af4f40453a9c84363bde5d9a58466de7fbee2e)

gcc/fortran/expr.c

@@ -4346,7 +4346,9 @@ gfc_check_pointer_assign (gfc_expr *lvalue, gfc_expr *rvalue,
      contiguous.  Be lenient in the definition of what counts as
      contiguous.  */
 
-  if (lhs_attr.contiguous && !gfc_is_simply_contiguous (rvalue, false, true))
+  if (lhs_attr.contiguous
+      && lhs_attr.dimension > 0
+      && !gfc_is_simply_contiguous (rvalue, false, true))
     gfc_warning (OPT_Wextra, "Assignment to contiguous pointer from "
 		 "non-contiguous target at %L", &rvalue->where);
 

gcc/testsuite/gfortran.dg/pr95503.f90

+! { dg-do compile }
+! PR fortran/95503 - ICE in gfc_is_simply_contiguous
+
+program p
+  complex, target :: a
+  real, pointer, contiguous :: b => a%re ! { dg-error "not an array pointer" }
+end