Fix implicit mapping for array slices on lexically-enclosing data constructs (PR70828)

2018-08-28  Julian Brown  <julian@codesourcery.com>
	    Cesar Philippidis  <cesar@codesourcery.com>

	gcc/
	* gimplify.cc (oacc_array_mapping_info): New struct.
	(gimplify_omp_ctx): Add decl_data_clause hash map.
	(new_omp_context): Zero-initialise above.
	(delete_omp_context): Delete above if allocated.
	(gimplify_scan_omp_clauses): Scan for array mappings on data constructs,
	and record in above map.
	(gomp_oacc_needs_data_present): New function.
	(gimplify_adjust_omp_clauses_1): Handle data mappings (e.g. array
	slices) declared in lexically-enclosing data constructs.
	* omp-low.cc (lower_omp_target): Allow decl for bias not to be present
	in OpenACC context.

	gcc/testsuite/
	* c-c++-common/goacc/acc-data-chain.c: New test.
	* gfortran.dg/goacc/pr70828.f90: New test.

	libgomp/
	* testsuite/libgomp.oacc-c-c++-common/pr70828.c: New test.
	* testsuite/libgomp.oacc-fortran/implicit_copy.f90: New test.
	* testsuite/libgomp.oacc-fortran/pr70828.f90: New test.
	* testsuite/libgomp.oacc-fortran/pr70828-2.f90: New test.
	* testsuite/libgomp.oacc-fortran/pr70828-3.f90: New test.
	* testsuite/libgomp.oacc-fortran/pr70828-4.f90: New test.
	* testsuite/libgomp.oacc-fortran/pr70828-5.f90: New test.
	* testsuite/libgomp.oacc-fortran/pr70828-6.f90: New test.

7 files changed, 223 insertions, 7 deletions

diff --git a/gcc/ChangeLog.omp b/gcc/ChangeLog.omp
index ea0d696..d9ec563 100644
--- a/gcc/ChangeLog.omp
+++ b/gcc/ChangeLog.omp
@@ -1,3 +1,18 @@
+2018-08-28  Julian Brown  <julian@codesourcery.com>
+            Cesar Philippidis  <cesar@codesourcery.com>
+
+	* gimplify.cc (oacc_array_mapping_info): New struct.
+	(gimplify_omp_ctx): Add decl_data_clause hash map.
+	(new_omp_context): Zero-initialise above.
+	(delete_omp_context): Delete above if allocated.
+	(gimplify_scan_omp_clauses): Scan for array mappings on data constructs,
+	and record in above map.
+	(gomp_oacc_needs_data_present): New function.
+	(gimplify_adjust_omp_clauses_1): Handle data mappings (e.g. array
+	slices) declared in lexically-enclosing data constructs.
+	* omp-low.cc (lower_omp_target): Allow decl for bias not to be present
+	in OpenACC context.
+
 2018-10-05  Nathan Sidwell  <nathan@acm.org>
 	    Tom de Vries  <tdevries@suse.de>
 	    Thomas Schwinge  <thomas@codesourcery.com>
diff --git a/gcc/fortran/trans-openmp.cc b/gcc/fortran/trans-openmp.cc
index 504dd6d..42eb069 100644
--- a/gcc/fortran/trans-openmp.cc
+++ b/gcc/fortran/trans-openmp.cc
@@ -1488,9 +1488,13 @@ gfc_omp_finish_clause (tree c, gimple_seq *pre_p, bool openacc)
 
   tree decl = OMP_CLAUSE_DECL (c);
 
-  /* Assumed-size arrays can't be mapped implicitly, they have to be
-     mapped explicitly using array sections.  */
-  if (TREE_CODE (decl) == PARM_DECL
+  /* Assumed-size arrays can't be mapped implicitly, they have to be mapped
+     explicitly using array sections.  An exception is if the array is
+     mapped explicitly in an enclosing data construct for OpenACC, in which
+     case we see GOMP_MAP_FORCE_PRESENT here and do not need to raise an
+     error.  */
+  if (OMP_CLAUSE_MAP_KIND (c) != GOMP_MAP_FORCE_PRESENT
+      && TREE_CODE (decl) == PARM_DECL
       && GFC_ARRAY_TYPE_P (TREE_TYPE (decl))
       && GFC_TYPE_ARRAY_AKIND (TREE_TYPE (decl)) == GFC_ARRAY_UNKNOWN
       && GFC_TYPE_ARRAY_UBOUND (TREE_TYPE (decl),
diff --git a/gcc/gimplify.cc b/gcc/gimplify.cc
index 8c44d0c..046527c 100644
--- a/gcc/gimplify.cc
+++ b/gcc/gimplify.cc
@@ -222,6 +222,17 @@ enum gimplify_defaultmap_kind
   GDMK_POINTER
 };
 
+/* Used to record clauses representing array slices on data directives that
+   may affect implicit mapping semantics on enclosed OpenACC parallel/kernels
+   regions.  PSET is used for Fortran array slices with array descriptors,
+   or NULL otherwise.  */
+struct oacc_array_mapping_info
+{
+  tree mapping;
+  tree pset;
+  tree pointer;
+};
+
 struct gimplify_omp_ctx
 {
   struct gimplify_omp_ctx *outer_context;
@@ -242,6 +253,7 @@ struct gimplify_omp_ctx
   bool has_depend;
   bool in_for_exprs;
   int defaultmap[5];
+  hash_map<tree, oacc_array_mapping_info> *decl_data_clause;
 };
 
 static struct gimplify_ctx *gimplify_ctxp;
@@ -471,6 +483,7 @@ new_omp_context (enum omp_region_type region_type)
   c->defaultmap[GDMK_AGGREGATE] = GOVD_MAP;
   c->defaultmap[GDMK_ALLOCATABLE] = GOVD_MAP;
   c->defaultmap[GDMK_POINTER] = GOVD_MAP;
+  c->decl_data_clause = NULL;
 
   return c;
 }
@@ -483,6 +496,8 @@ delete_omp_context (struct gimplify_omp_ctx *c)
   splay_tree_delete (c->variables);
   delete c->privatized_types;
   c->loop_iter_var.release ();
+  if (c->decl_data_clause)
+    delete c->decl_data_clause;
   XDELETE (c);
 }
 
@@ -9509,8 +9524,41 @@ gimplify_scan_omp_clauses (tree *list_p, gimple_seq *pre_p,
 	    case OMP_TARGET:
 	      break;
 	    case OACC_DATA:
-	      if (TREE_CODE (TREE_TYPE (decl)) != ARRAY_TYPE)
-		break;
+	      {
+		tree base_ptr = OMP_CLAUSE_CHAIN (c);
+		tree pset = NULL;
+		if (base_ptr
+		    && OMP_CLAUSE_CODE (base_ptr) == OMP_CLAUSE_MAP
+		    && OMP_CLAUSE_MAP_KIND (base_ptr) == GOMP_MAP_TO_PSET)
+		  {
+		    pset = base_ptr;
+		    base_ptr = OMP_CLAUSE_CHAIN (base_ptr);
+		  }
+		if (base_ptr
+		    && OMP_CLAUSE_CODE (base_ptr) == OMP_CLAUSE_MAP
+		    && OMP_CLAUSE_MAP_KIND (c) != GOMP_MAP_TO_PSET
+		    && ((OMP_CLAUSE_MAP_KIND (base_ptr)
+			 == GOMP_MAP_FIRSTPRIVATE_POINTER)
+			|| OMP_CLAUSE_MAP_KIND (base_ptr) == GOMP_MAP_POINTER))
+		  {
+		    /* If we have an array descriptor, fish the right base
+		       address variable to use out of that (otherwise we'd have
+		       to deconstruct "arr.data" in the subsequent pointer
+		       mapping).  */
+	            tree base_addr = pset ? OMP_CLAUSE_DECL (pset)
+					  : OMP_CLAUSE_DECL (base_ptr);
+		    if (!ctx->decl_data_clause)
+		      ctx->decl_data_clause
+			= new hash_map<tree, oacc_array_mapping_info>;
+		    oacc_array_mapping_info ai;
+		    ai.mapping = unshare_expr (c);
+		    ai.pset = pset ? unshare_expr (pset) : NULL;
+		    ai.pointer = unshare_expr (base_ptr);
+		    ctx->decl_data_clause->put (base_addr, ai);
+		  }
+		if (TREE_CODE (TREE_TYPE (decl)) != ARRAY_TYPE)
+		  break;
+	      }
 	      /* FALLTHRU */
 	    case OMP_TARGET_DATA:
 	    case OMP_TARGET_ENTER_DATA:
@@ -11084,6 +11132,46 @@ struct gimplify_adjust_omp_clauses_data
   gimple_seq *pre_p;
 };
 
+/* For OpenACC parallel and kernels regions, the implicit data mappings for
+   arrays must respect explicit data clauses set by a containing acc data
+   region.  Specifically, an array section on the data clause must be
+   transformed into an equivalent PRESENT mapping on the inner parallel or
+   kernels region.  This function returns a pointer to an
+   oacc_array_mapping_info if an array slice of DECL is specified in a
+   lexically-enclosing data construct, or returns NULL otherwise.  */
+
+static oacc_array_mapping_info *
+gomp_oacc_needs_data_present (tree decl)
+{
+  gimplify_omp_ctx *ctx = NULL;
+
+  if (gimplify_omp_ctxp->region_type != ORT_ACC_PARALLEL
+      && gimplify_omp_ctxp->region_type != ORT_ACC_KERNELS)
+    return NULL;
+
+  if (TREE_CODE (TREE_TYPE (decl)) != ARRAY_TYPE
+      && TREE_CODE (TREE_TYPE (decl)) != POINTER_TYPE
+      && TREE_CODE (TREE_TYPE (decl)) != RECORD_TYPE
+      && (TREE_CODE (TREE_TYPE (decl)) != POINTER_TYPE
+	  || TREE_CODE (TREE_TYPE (TREE_TYPE (decl))) != ARRAY_TYPE))
+    return NULL;
+
+  decl = get_base_address (decl);
+
+  for (ctx = gimplify_omp_ctxp->outer_context; ctx; ctx = ctx->outer_context)
+    {
+      oacc_array_mapping_info *ret;
+
+      if (ctx->region_type != ORT_ACC_DATA)
+	break;
+
+      if (ctx->decl_data_clause && (ret = ctx->decl_data_clause->get (decl)))
+	return ret;
+    }
+
+  return NULL;
+}
+
 /* For all variables that were not actually used within the context,
    remove PRIVATE, SHARED, and FIRSTPRIVATE clauses.  */
 
@@ -11207,6 +11295,7 @@ gimplify_adjust_omp_clauses_1 (splay_tree_node n, void *data)
   clause = build_omp_clause (input_location, code);
   OMP_CLAUSE_DECL (clause) = decl;
   OMP_CLAUSE_CHAIN (clause) = chain;
+  oacc_array_mapping_info *array_info;
   if (private_debug)
     OMP_CLAUSE_PRIVATE_DEBUG (clause) = 1;
   else if (code == OMP_CLAUSE_PRIVATE && (flags & GOVD_PRIVATE_OUTER_REF))
@@ -11215,6 +11304,56 @@ gimplify_adjust_omp_clauses_1 (splay_tree_node n, void *data)
 	   && (flags & GOVD_WRITTEN) == 0
 	   && omp_shared_to_firstprivate_optimizable_decl_p (decl))
     OMP_CLAUSE_SHARED_READONLY (clause) = 1;
+  else if ((code == OMP_CLAUSE_MAP || code == OMP_CLAUSE_FIRSTPRIVATE)
+	   && (array_info = gomp_oacc_needs_data_present (decl)))
+    {
+      tree mapping = array_info->mapping;
+      tree pointer = array_info->pointer;
+
+      if (code == OMP_CLAUSE_FIRSTPRIVATE)
+	/* Oops, we have the wrong type of clause.  Rebuild it.  */
+	clause = build_omp_clause (OMP_CLAUSE_LOCATION (clause),
+				   OMP_CLAUSE_MAP);
+
+      OMP_CLAUSE_DECL (clause) = unshare_expr (OMP_CLAUSE_DECL (mapping));
+      OMP_CLAUSE_SET_MAP_KIND (clause, GOMP_MAP_FORCE_PRESENT);
+      OMP_CLAUSE_SIZE (clause) = unshare_expr (OMP_CLAUSE_SIZE (mapping));
+
+      /* Create a new data clause for the firstprivate pointer.  */
+      tree nc = build_omp_clause (OMP_CLAUSE_LOCATION (clause),
+				  OMP_CLAUSE_MAP);
+      OMP_CLAUSE_DECL (nc) = unshare_expr (OMP_CLAUSE_DECL (pointer));
+      OMP_CLAUSE_SET_MAP_KIND (nc, GOMP_MAP_POINTER);
+
+      /* For GOMP_MAP_FIRSTPRIVATE_POINTER, this is a bias, not a size.  */
+      OMP_CLAUSE_SIZE (nc) = unshare_expr (OMP_CLAUSE_SIZE (pointer));
+
+      /* Create a new data clause for the PSET, if present.  */
+      tree psetc = NULL;
+      if (array_info->pset)
+	{
+	  tree pset = array_info->pset;
+	  psetc = build_omp_clause (OMP_CLAUSE_LOCATION (clause),
+				    OMP_CLAUSE_MAP);
+	  OMP_CLAUSE_DECL (psetc) = unshare_expr (OMP_CLAUSE_DECL (pset));
+	  OMP_CLAUSE_SIZE (psetc) = unshare_expr (OMP_CLAUSE_SIZE (pset));
+	  OMP_CLAUSE_SET_MAP_KIND (psetc, GOMP_MAP_TO_PSET);
+	  OMP_CLAUSE_CHAIN (psetc) = nc;
+	}
+
+      gimplify_omp_ctx *ctx = gimplify_omp_ctxp;
+      gimplify_omp_ctxp = ctx->outer_context;
+      gimplify_expr (&OMP_CLAUSE_DECL (clause), pre_p, NULL,
+		     is_gimple_lvalue, fb_lvalue);
+      gimplify_expr (&OMP_CLAUSE_SIZE (clause), pre_p, NULL,
+		     is_gimple_val, fb_rvalue);
+      gimplify_expr (&OMP_CLAUSE_SIZE (nc), pre_p, NULL, is_gimple_val,
+		     fb_rvalue);
+      gimplify_omp_ctxp = ctx;
+
+      OMP_CLAUSE_CHAIN (nc) = OMP_CLAUSE_CHAIN (clause);
+      OMP_CLAUSE_CHAIN (clause) = psetc ? psetc : nc;
+    }
   else if (code == OMP_CLAUSE_FIRSTPRIVATE && (flags & GOVD_EXPLICIT) == 0)
     OMP_CLAUSE_FIRSTPRIVATE_IMPLICIT (clause) = 1;
   else if (code == OMP_CLAUSE_MAP && (flags & GOVD_MAP_0LEN_ARRAY) != 0)
diff --git a/gcc/omp-low.cc b/gcc/omp-low.cc
index edc22e2..5dbff93 100644
--- a/gcc/omp-low.cc
+++ b/gcc/omp-low.cc
@@ -14215,8 +14215,14 @@ lower_omp_target (gimple_stmt_iterator *gsi_p, omp_context *ctx)
 		x = fold_convert_loc (clause_loc, type, x);
 		if (!integer_zerop (OMP_CLAUSE_SIZE (c)))
 		  {
-		    tree bias = OMP_CLAUSE_SIZE (c);
-		    if (DECL_P (bias))
+		    tree bias = OMP_CLAUSE_SIZE (c), remapped_bias;
+		    if (is_gimple_omp_oacc (ctx->stmt))
+		      {
+			if (DECL_P (bias)
+			    && (remapped_bias = maybe_lookup_decl (bias, ctx)))
+			  bias = remapped_bias;
+		      }
+		    else if (DECL_P (bias))
 		      bias = lookup_decl (bias, ctx);
 		    bias = fold_convert_loc (clause_loc, sizetype, bias);
 		    bias = fold_build1_loc (clause_loc, NEGATE_EXPR, sizetype,
diff --git a/gcc/testsuite/ChangeLog.omp b/gcc/testsuite/ChangeLog.omp
index 4108c8d..9be3866 100644
--- a/gcc/testsuite/ChangeLog.omp
+++ b/gcc/testsuite/ChangeLog.omp
@@ -1,3 +1,9 @@
+2018-08-28  Julian Brown  <julian@codesourcery.com>
+	    Cesar Philippidis  <cesar@codesourcery.com>
+
+	* c-c++-common/goacc/acc-data-chain.c: New test.
+	* gfortran.dg/goacc/pr70828.f90: New test.
+
 2018-10-05  Nathan Sidwell  <nathan@acm.org>
 	    Tom de Vries  <tdevries@suse.de>
 	    Thomas Schwinge  <thomas@codesourcery.com>
diff --git a/gcc/testsuite/c-c++-common/goacc/acc-data-chain.c b/gcc/testsuite/c-c++-common/goacc/acc-data-chain.c
new file mode 100644
index 0000000..8a039be
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/goacc/acc-data-chain.c
@@ -0,0 +1,24 @@
+/* Ensure that the gimplifier does not remove any existing clauses as
+   it inserts new implicit data clauses.  */
+
+/* { dg-additional-options "-fdump-tree-gimple" }  */
+
+#define N 100
+static int a[N], b[N];
+
+int main(int argc, char *argv[])
+{
+  int i;
+
+#pragma acc data copyin(a[0:N]) copyout (b[0:N])
+  {
+#pragma acc parallel loop
+    for (i = 0; i < N; i++)
+      b[i] = a[i];
+  }
+
+ return 0;
+}
+
+// { dg-final { scan-tree-dump-times "omp target oacc_data map\\(from:b\\\[0\\\] \\\[len: 400\\\]\\) map\\(to:a\\\[0\\\] \\\[len: 400\\\]\\)" 1 "gimple" } }
+// { dg-final { scan-tree-dump-times "omp target oacc_parallel map\\(force_present:b\\\[0\\\] \\\[len: 400\\\]\\) map.alloc:b \\\[pointer assign, bias: 0\\\]\\) map\\(force_present:a\\\[0\\\] \\\[len: 400\\\]\\) map\\(alloc:a \\\[pointer assign, bias: 0\\\]\\)" 1 "gimple" } }
diff --git a/gcc/testsuite/gfortran.dg/goacc/pr70828.f90 b/gcc/testsuite/gfortran.dg/goacc/pr70828.f90
new file mode 100644
index 0000000..2e58120
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/goacc/pr70828.f90
@@ -0,0 +1,22 @@
+! Ensure that pointer mappings are preserved in nested parallel
+! constructs.
+
+! { dg-additional-options "-fdump-tree-gimple" }
+
+program test
+  integer, parameter :: n = 100
+  integer i, data(n)
+
+  data(:) = 0
+
+  !$acc data copy(data(5:n-10))
+  !$acc parallel loop
+  do i = 10, n - 10
+     data(i) = i
+  end do
+  !$acc end parallel loop
+  !$acc end data
+end program test
+
+! { dg-final { scan-tree-dump-times "omp target oacc_data map\\(tofrom:MEM\\\[\\(c_char \\*\\)\_\[0-9\]+\\\] \\\[len: _\[0-9\]+\\\]\\) map\\(alloc:data \\\[pointer assign, bias: _\[0-9\]+\\\]\\)" 1 "gimple" } }
+! { dg-final { scan-tree-dump-times "omp target oacc_parallel map\\(force_present:MEM\\\[\\(c_char \\*\\)D\\.\[0-9\]+\\\] \\\[len: D\\.\[0-9\]+\\\]\\) map\\(alloc:data \\\[pointer assign, bias: D\\.\[0-9\]+\\\]\\)" 1 "gimple" } }