Fix switch conversion in offloading functions

2018-03-26  Tom de Vries  <tom@codesourcery.com>

	PR tree-optimization/85063
	* omp-general.c (offloading_function_p): New function.  Factor out
	of ...
	* omp-offload.c (pass_omp_target_link::gate): ... here.
	* omp-general.h (offloading_function_p): Declare.
	* tree-switch-conversion.c (build_one_array): Mark CSWTCH.x variable
	with attribute omp declare target for offloading functions.

	* testsuite/libgomp.c/switch-conversion-2.c: New test.
	* testsuite/libgomp.c/switch-conversion.c: New test.
	* testsuite/libgomp.oacc-c-c++-common/switch-conversion-2.c: New test.
	* testsuite/libgomp.oacc-c-c++-common/switch-conversion.c: New test.

From-SVN: r258852

gcc/ChangeLog

@@ -1,3 +1,13 @@
+2018-03-26  Tom de Vries  <tom@codesourcery.com>
+
+	PR tree-optimization/85063
+	* omp-general.c (offloading_function_p): New function.  Factor out
+	of ...
+	* omp-offload.c (pass_omp_target_link::gate): ... here.
+	* omp-general.h (offloading_function_p): Declare.
+	* tree-switch-conversion.c (build_one_array): Mark CSWTCH.x variable
+	with attribute omp declare target for offloading functions.
+
 2018-03-24  Richard Sandiford  <richard.sandiford@linaro.org>
 
 	PR tree-optimization/84005

gcc/omp-general.c

@@ -612,6 +612,16 @@ oacc_get_fn_attrib (tree fn)
   return lookup_attribute (OACC_FN_ATTRIB, DECL_ATTRIBUTES (fn));
 }
 
+/* Return true if FN is an OpenMP or OpenACC offloading function.  */
+
+bool
+offloading_function_p (tree fn)
+{
+  tree attrs = DECL_ATTRIBUTES (fn);
+  return (lookup_attribute ("omp declare target", attrs)
+	  || lookup_attribute ("omp target entrypoint", attrs));
+}
+
 /* Extract an oacc execution dimension from FN.  FN must be an
    offloaded function or routine that has already had its execution
    dimensions lowered to the target-specific values.  */

gcc/omp-general.h

@@ -85,6 +85,7 @@ extern void oacc_replace_fn_attrib (tree fn, tree dims);
 extern void oacc_set_fn_attrib (tree fn, tree clauses, vec<tree> *args);
 extern tree oacc_build_routine_dims (tree clauses);
 extern tree oacc_get_fn_attrib (tree fn);
+extern bool offloading_function_p (tree fn);
 extern int oacc_get_fn_dim_size (tree fn, int axis);
 extern int oacc_get_ifn_dim_arg (const gimple *stmt);
 

gcc/omp-offload.c

@@ -1967,9 +1967,7 @@ public:
   virtual bool gate (function *fun)
     {
 #ifdef ACCEL_COMPILER
-      tree attrs = DECL_ATTRIBUTES (fun->decl);
+      return offloading_function_p (fun->decl);
-      return lookup_attribute ("omp declare target", attrs)
-	     || lookup_attribute ("omp target entrypoint", attrs);
 #else
       (void) fun;
       return false;

gcc/tree-switch-conversion.c

@@ -49,6 +49,7 @@ Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
 #include "alloc-pool.h"
 #include "target.h"
 #include "tree-into-ssa.h"
+#include "omp-general.h"
 
 /* ??? For lang_hooks.types.type_for_mode, but is there a word_mode
    type in the GIMPLE type system that is language-independent?  */
@@ -1162,6 +1163,10 @@ build_one_array (gswitch *swtch, int num, tree arr_index_type,
       TREE_CONSTANT (decl) = 1;
       TREE_READONLY (decl) = 1;
       DECL_IGNORED_P (decl) = 1;
+      if (offloading_function_p (cfun->decl))
+	DECL_ATTRIBUTES (decl)
+	  = tree_cons (get_identifier ("omp declare target"), NULL_TREE,
+		       NULL_TREE);
       varpool_node::finalize_decl (decl);
 
       fetch = build4 (ARRAY_REF, value_type, decl, tidx, NULL_TREE,

libgomp/ChangeLog

@@ -1,3 +1,11 @@
+2018-03-26  Tom de Vries  <tom@codesourcery.com>
+
+	PR tree-optimization/85063
+	* testsuite/libgomp.c/switch-conversion-2.c: New test.
+	* testsuite/libgomp.c/switch-conversion.c: New test.
+	* testsuite/libgomp.oacc-c-c++-common/switch-conversion-2.c: New test.
+	* testsuite/libgomp.oacc-c-c++-common/switch-conversion.c: New test.
+
 2018-03-25  Thomas Koenig  <tkoenig@gcc.gnu.org>
 
 	PR fortran/84381

libgomp/testsuite/libgomp.c/switch-conversion-2.c

@@ -0,0 +1,31 @@
+/* PR tree-optimization/85063 */
+/* { dg-additional-options "-ftree-switch-conversion" } */
+
+#include <stdlib.h>
+
+int
+main (void)
+{
+  int n[1];
+
+  n[0] = 3;
+
+#pragma omp target
+  {
+    int m = n[0];
+    switch (m & 3)
+    {
+    case 0: m = 4; break;
+    case 1: m = 3; break;
+    case 2: m = 2; break;
+    default:
+      m = 1; break;
+    }
+    n[0] = m;
+  }
+
+  if (n[0] != 1)
+    abort ();
+
+  return 0;
+}

libgomp/testsuite/libgomp.c/switch-conversion.c

@@ -0,0 +1,36 @@
+/* PR tree-optimization/85063 */
+/* { dg-additional-options "-ftree-switch-conversion" } */
+
+#include <stdlib.h>
+
+#pragma omp declare target
+static int __attribute__((noinline)) foo (int n)
+{
+  switch (n & 3)
+    {
+    case 0: return 4;
+    case 1: return 3;
+    case 2: return 2;
+    default:
+      return 1;
+    }
+}
+#pragma omp end declare target
+
+int
+main (void)
+{
+  int n[1];
+
+  n[0] = 4;
+
+#pragma omp target
+  {
+    n[0] = foo (n[0]);
+  }
+
+  if (n[0] != 4)
+    abort ();
+
+  return 0;
+}

libgomp/testsuite/libgomp.oacc-c-c++-common/switch-conversion-2.c

@@ -0,0 +1,31 @@
+/* PR tree-optimization/85063 */
+/* { dg-additional-options "-ftree-switch-conversion" } */
+
+#include <stdlib.h>
+
+int
+main (void)
+{
+  int n[1];
+
+  n[0] = 3;
+
+#pragma acc parallel copy(n)
+  {
+    int m = n[0];
+    switch (m & 3)
+    {
+    case 0: m = 4; break;
+    case 1: m = 3; break;
+    case 2: m = 2; break;
+    default:
+      m = 1; break;
+    }
+    n[0] = m;
+  }
+
+  if (n[0] != 1)
+    abort ();
+
+  return 0;
+}

libgomp/testsuite/libgomp.oacc-c-c++-common/switch-conversion.c

@@ -0,0 +1,35 @@
+/* PR tree-optimization/85063 */
+/* { dg-additional-options "-ftree-switch-conversion" } */
+
+#include <stdlib.h>
+
+#pragma acc routine seq
+static int __attribute__((noinline)) foo (int n)
+{
+  switch (n & 3)
+    {
+    case 0: return 4;
+    case 1: return 3;
+    case 2: return 2;
+    default:
+      return 1;
+    }
+}
+
+int
+main (void)
+{
+  int n[1];
+
+  n[0] = 4;
+
+#pragma acc parallel copy(n)
+  {
+    n[0] = foo (n[0]);
+  }
+
+  if (n[0] != 4)
+    abort ();
+
+  return 0;
+}