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[patch, openmp/openacc] Allow Fortran parameters in map/copy.


This patch allows Fortran "parameter" named constants to be named in OpenMP map and OpenACC copy directives.

Right now, the compiler just says something like:

     !$omp target data map(tofrom:N,x)
                                 1
  Error: Object 'n' is not a variable at (1)

This is technically correct, but is surprising to the user and AFAICT the OpenMP/OpenACC documents don't say you can't name parameters, so I'd like it to be allowed.

Also, I suspect the support request that led me here originated from code originally written for another toolchain, so this is a portability issue.

With this patch the compiler allows the parameter in the directive, but just ignores it (deletes it), so that it has no effect. This is safe since the named constant will have been substituted for the actual value everywhere it occurs. If that is not true in some case (can it happen?), I believe it will be automatically mapped in the same way other variables are.

Using parameters in device_resident, deviceptr, private, reduction, etc., remains an error.

OK to commit?

Andrew
Allow Fortran parameters in map/copy directives.

2019-07-05  Andrew Stubbs  <ams@codesourcery.com>

	gcc/fortran/
	* gfortran.h (gfc_free_omp_namelist_entry): New prototype.
	* match.c (gfc_free_omp_namelist): Break contents out into ...
	(gfc_free_omp_namelist_entry): ... here.
	* openmp.c (resolve_omp_clauses): Delete parameters in map to and from.

	gcc/testsuite/
	* gfortran.dg/goacc/parameter.f95: Allow parameters in copy.
	* gfortran.dg/gomp/map-1.f90: Allow parameters in map, only.

diff --git a/gcc/fortran/gfortran.h b/gcc/fortran/gfortran.h
index b1f7bd0604a..5363cbd331b 100644
--- a/gcc/fortran/gfortran.h
+++ b/gcc/fortran/gfortran.h
@@ -3181,6 +3181,7 @@ void gfc_free_iterator (gfc_iterator *, int);
 void gfc_free_forall_iterator (gfc_forall_iterator *);
 void gfc_free_alloc_list (gfc_alloc *);
 void gfc_free_namelist (gfc_namelist *);
+void gfc_free_omp_namelist_entry (gfc_omp_namelist *);
 void gfc_free_omp_namelist (gfc_omp_namelist *);
 void gfc_free_equiv (gfc_equiv *);
 void gfc_free_equiv_until (gfc_equiv *, gfc_equiv *);
diff --git a/gcc/fortran/match.c b/gcc/fortran/match.c
index 0f3b2132122..51c9e9ef5ed 100644
--- a/gcc/fortran/match.c
+++ b/gcc/fortran/match.c
@@ -5373,6 +5373,23 @@ gfc_free_namelist (gfc_namelist *name)
 }
 
 
+/* Free an OpenMP namelist entry.  */
+
+void
+gfc_free_omp_namelist_entry (gfc_omp_namelist *name)
+{
+  gfc_free_expr (name->expr);
+  if (name->udr)
+    {
+      if (name->udr->combiner)
+	gfc_free_statement (name->udr->combiner);
+      if (name->udr->initializer)
+	gfc_free_statement (name->udr->initializer);
+      free (name->udr);
+    }
+  free (name);
+}
+
 /* Free an OpenMP namelist structure.  */
 
 void
@@ -5382,17 +5399,8 @@ gfc_free_omp_namelist (gfc_omp_namelist *name)
 
   for (; name; name = n)
     {
-      gfc_free_expr (name->expr);
-      if (name->udr)
-	{
-	  if (name->udr->combiner)
-	    gfc_free_statement (name->udr->combiner);
-	  if (name->udr->initializer)
-	    gfc_free_statement (name->udr->initializer);
-	  free (name->udr);
-	}
       n = name->next;
-      free (name);
+      gfc_free_omp_namelist_entry (name);
     }
 }
 
diff --git a/gcc/fortran/openmp.c b/gcc/fortran/openmp.c
index 1c7bce6c300..d06221b41ed 100644
--- a/gcc/fortran/openmp.c
+++ b/gcc/fortran/openmp.c
@@ -4165,6 +4165,22 @@ resolve_omp_clauses (gfc_code *code, gfc_omp_clauses *omp_clauses,
 		   "clause at %L", &code->loc);
     }
 
+  /* Remove no-op mappings, such as parameters.  */
+  gfc_omp_namelist **parent = &omp_clauses->lists[OMP_LIST_MAP];
+  for (n = omp_clauses->lists[OMP_LIST_MAP]; n; n = n->next)
+    {
+      if ((n->u.map_op == OMP_MAP_TO
+	   || n->u.map_op == OMP_MAP_FROM
+	   || n->u.map_op == OMP_MAP_TOFROM)
+	  && n->sym->attr.flavor == FL_PARAMETER)
+	{
+	  *parent = n->next;
+	  gfc_free_omp_namelist_entry (n);
+	}
+      else
+	parent = &n->next;
+    }
+
   /* Check that no symbol appears on multiple clauses, except that
      a symbol can appear on both firstprivate and lastprivate.  */
   for (list = 0; list < OMP_LIST_NUM; list++)
diff --git a/gcc/testsuite/gfortran.dg/goacc/parameter.f95 b/gcc/testsuite/gfortran.dg/goacc/parameter.f95
index 84274611915..edfaeeadc76 100644
--- a/gcc/testsuite/gfortran.dg/goacc/parameter.f95
+++ b/gcc/testsuite/gfortran.dg/goacc/parameter.f95
@@ -7,7 +7,7 @@ contains
     integer :: i
     integer, parameter :: a = 1
     !$acc declare device_resident (a) ! { dg-error "PARAMETER" }
-    !$acc data copy (a) ! { dg-error "not a variable" }
+    !$acc data copy (a) ! This is permitted.
     !$acc end data
     !$acc data deviceptr (a) ! { dg-error "not a variable" }
     !$acc end data
diff --git a/gcc/testsuite/gfortran.dg/gomp/map-1.f90 b/gcc/testsuite/gfortran.dg/gomp/map-1.f90
index e78b56c8f39..abe448a33f9 100644
--- a/gcc/testsuite/gfortran.dg/gomp/map-1.f90
+++ b/gcc/testsuite/gfortran.dg/gomp/map-1.f90
@@ -18,7 +18,7 @@ subroutine test(aas)
   !$omp target map(j)
   !$omp end target
 
-  !$omp target map(p) ! { dg-error "Object 'p' is not a variable" }
+  !$omp target map(p)
   !$omp end target
 
   !$omp target map(j(1))

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