Add 'gcc.target/nvptx/softstack-decl-1.c', 'gcc.target/nvptx/uniform-simt-decl-1.c'

... to document the status quo re implicit (via 'need_softstack_decl',
'need_unisimt_decl') and explicit declarations of '__nvptx_stacks',
'__nvptx_uni'.

	gcc/testsuite/
	* gcc.target/nvptx/softstack-decl-1.c: New.
	* gcc.target/nvptx/uniform-simt-decl-1.c: Likewise.

3 files changed, 52 insertions, 0 deletions

diff --git a/gcc/testsuite/ChangeLog.omp b/gcc/testsuite/ChangeLog.omp
index 71fa411..ea37440 100644
--- a/gcc/testsuite/ChangeLog.omp
+++ b/gcc/testsuite/ChangeLog.omp
@@ -1,5 +1,8 @@
 2023-01-20  Thomas Schwinge  <thomas@codesourcery.com>
 
+	* gcc.target/nvptx/softstack-decl-1.c: New.
+	* gcc.target/nvptx/uniform-simt-decl-1.c: Likewise.
+
 	* gcc.target/nvptx/nvptx.exp
 	(check_effective_target_default_ptx_isa_version_at_least_6_0):
 	New.
diff --git a/gcc/testsuite/gcc.target/nvptx/softstack-decl-1.c b/gcc/testsuite/gcc.target/nvptx/softstack-decl-1.c
new file mode 100644
index 0000000..c502eac
--- /dev/null
+++ b/gcc/testsuite/gcc.target/nvptx/softstack-decl-1.c
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+/* { dg-options {-save-temps -O0 -msoft-stack} } */
+
+extern void *__nvptx_stacks[32] __attribute__((shared,nocommon));
+
+void *f()
+{
+  /* Implicit '__nvptx_stacks' usage for frame; per 'init_softstack_frame':
+     { dg-final { scan-assembler-times {mov\.u64 %fstmp2, __nvptx_stacks;} 1 } }
+  */
+  void *stack_array[123];
+  /* Explicit '__nvptx_stacks' usage.  */ 
+  stack_array[5] = __nvptx_stacks[0];
+  return stack_array[5];
+}
+
+/* The implicit (via 'need_softstack_decl') and explicit declarations of
+   '__nvptx_stacks' are both emitted:
+   { dg-final { scan-assembler-times {(?n)\.extern .* __nvptx_stacks\[32\];} 2 } }
+*/
diff --git a/gcc/testsuite/gcc.target/nvptx/uniform-simt-decl-1.c b/gcc/testsuite/gcc.target/nvptx/uniform-simt-decl-1.c
new file mode 100644
index 0000000..486456a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/nvptx/uniform-simt-decl-1.c
@@ -0,0 +1,29 @@
+/* { dg-do compile } */
+/* { dg-options {-save-temps -O0 -muniform-simt} } */
+
+extern unsigned __nvptx_uni[32] __attribute__((shared,nocommon));
+
+enum memmodel
+{
+  MEMMODEL_RELAXED = 0,
+};
+
+int a = 0;
+
+int f (void)
+{
+  /* Explicit '__nvptx_uni' usage.  */
+  __builtin_printf("%u\n", __nvptx_uni[0]);
+
+  /* Implicit '__nvptx_uni' usage; per 'nvptx_init_unisimt_predicate':
+     { dg-final { scan-assembler-times {mov\.u64 %r[0-9]+, __nvptx_uni;} 1 } }
+  */
+  int expected = 1;
+  return __atomic_compare_exchange_n (&a, &expected, 0, 0, MEMMODEL_RELAXED,
+				      MEMMODEL_RELAXED);
+}
+
+/* The implicit (via 'need_unisimt_decl') and explicit declarations of
+   '__nvptx_uni' are both emitted:
+   { dg-final { scan-assembler-times {(?n)\.extern .* __nvptx_uni\[32\];} 2 } }
+*/