openmp: Optimize DECL_IN_CONSTANT_POOL vars in target regions

DECL_IN_CONSTANT_POOL are shared and thus don't really get emitted in the
BLOCK where they are used, so for OpenMP target regions that have initializers
gimplified into copying from them we actually map them at runtime from host to
offload devices.  This patch instead marks them as "omp declare target", so
that they are on the target device from the beginning and don't need to be
copied there.

2020-02-09  Jakub Jelinek  <jakub@redhat.com>

	* gimplify.c (gimplify_adjust_omp_clauses_1): Promote
	DECL_IN_CONSTANT_POOL variables into "omp declare target" to avoid
	copying them around between host and target.

	* testsuite/libgomp.c/target-38.c: New test.

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index b46ea4f..34c0811 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2020-02-09  Jakub Jelinek  <jakub@redhat.com>
+
+       * gimplify.c (gimplify_adjust_omp_clauses_1): Promote
+       DECL_IN_CONSTANT_POOL variables into "omp declare target" to avoid
+       copying them around between host and target.
+
 2020-02-08  Andrew Pinski  <apinski@marvell.com>
 
        PR target/91927

diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index aafef78..a6205d6 100644 (file)
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -9906,6 +9906,22 @@ gimplify_adjust_omp_clauses_1 (splay_tree_node n, void *data)
          error ("%<_Atomic%> %qD in implicit %<map%> clause", decl);
          return 0;
        }
+      if (VAR_P (decl)
+         && DECL_IN_CONSTANT_POOL (decl)
+          && !lookup_attribute ("omp declare target",
+                               DECL_ATTRIBUTES (decl)))
+       {
+         tree id = get_identifier ("omp declare target");
+         DECL_ATTRIBUTES (decl)
+           = tree_cons (id, NULL_TREE, DECL_ATTRIBUTES (decl));
+         varpool_node *node = varpool_node::get (decl);
+         if (node)
+           {
+             node->offloadable = 1;
+             if (ENABLE_OFFLOADING)
+               g->have_offload = true;
+           }
+       }
     }
   else if (flags & GOVD_SHARED)
     {

diff --git a/libgomp/ChangeLog b/libgomp/ChangeLog
index ba14005..0740df8 100644 (file)
--- a/libgomp/ChangeLog
+++ b/libgomp/ChangeLog
@@ -1,3 +1,7 @@
+2020-02-09  Jakub Jelinek  <jakub@redhat.com>
+
+       * testsuite/libgomp.c/target-38.c: New test.
+
 2020-02-06  Jakub Jelinek  <jakub@redhat.com>
 
        PR libgomp/93515

diff --git a/libgomp/testsuite/libgomp.c/target-38.c b/libgomp/testsuite/libgomp.c/target-38.c
new file mode 100644 (file)
index 0000000..8169972
--- /dev/null
+++ b/libgomp/testsuite/libgomp.c/target-38.c
@@ -0,0 +1,28 @@
+#define A(n) n##0, n##1, n##2, n##3, n##4, n##5, n##6, n##7, n##8, n##9
+#define B(n) A(n##0), A(n##1), A(n##2), A(n##3), A(n##4), A(n##5), A(n##6), A(n##7), A(n##8), A(n##9)
+
+int
+foo (int x)
+{
+  int b[] = { B(4), B(5), B(6) };
+  return b[x];
+}
+
+int v[] = { 1, 2, 3, 4, 5, 6 };
+#pragma omp declare target to (foo, v)
+
+int
+main ()
+{
+  int i = 5;
+  asm ("" : "+g" (i));
+  #pragma omp target map(tofrom:i)
+  {
+    int a[] = { B(1), B(2), B(3) };
+    asm ("" : : "m" (a) : "memory");
+    i = a[i] + foo (i) + v[i & 63];
+  }
+  if (i != 105 + 405 + 6)
+    __builtin_abort ();
+  return 0;
+}