[committed][nvptx] Handle assignment to gang-level reduction variable

[Tom de Vries]

Hi,

this fixes an ICE when handling an assignment to a gang-level reduction
variable.

Committed to trunk.

Thanks,
- Tom

[nvptx] Handle assignment to gang-level reduction variable

2019-01-15  Tom de Vries  <tdevr...@suse.de>

        PR target/80547
        * config/nvptx/nvptx.c (nvptx_goacc_reduction_init): Handle
        lhs == NULL_TREE for gang-level reduction.

        * testsuite/libgomp.oacc-c-c++-common/gang-reduction-var-assignment.c:
        New test.

---
 gcc/config/nvptx/nvptx.c                                 |  3 ++-
 .../gang-reduction-var-assignment.c                      | 16 ++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/gcc/config/nvptx/nvptx.c b/gcc/config/nvptx/nvptx.c
index 03c0f82f4a2..23459e1c6f4 100644
--- a/gcc/config/nvptx/nvptx.c
+++ b/gcc/config/nvptx/nvptx.c
@@ -6242,7 +6242,8 @@ nvptx_goacc_reduction_init (gcall *call, offload_attrs 
*oa)
            init = var;
        }
 
-      gimplify_assign (lhs, init, &seq);
+      if (lhs != NULL_TREE)
+       gimplify_assign (lhs, init, &seq);
     }
 
   pop_gimplify_context (NULL);
diff --git 
a/libgomp/testsuite/libgomp.oacc-c-c++-common/gang-reduction-var-assignment.c 
b/libgomp/testsuite/libgomp.oacc-c-c++-common/gang-reduction-var-assignment.c
new file mode 100644
index 00000000000..05f58a4bddf
--- /dev/null
+++ 
b/libgomp/testsuite/libgomp.oacc-c-c++-common/gang-reduction-var-assignment.c
@@ -0,0 +1,16 @@
+/* { dg-xfail-run-if "PR88852" { openacc_host_selected } } */
+
+int
+main (void)
+{
+  int x = 123;
+
+#pragma acc parallel num_gangs(1) reduction (+: x)
+  {
+    x = 23;
+  }
+  if (x != 146)
+    __builtin_abort();
+
+  return 0;
+}