nvptx: Add '__builtin_alloca(0)' test cases [PR65181]

Documenting the status quo.  This specific behavior relates to a 1994 change
(Subversion r7229, Git commit 15fc002672d643fd9d93d220027b5cd2aefc632c).
That one, however, isn't to blame here: we'd otherwise of course run into
nvptx' 'sorry, unimplemented: target cannot support alloca'.

	PR target/65181
	gcc/testsuite/
	* gcc.target/nvptx/__builtin_alloca_0-1-O0.c: New.
	* gcc.target/nvptx/__builtin_alloca_0-1-O1.c: Likewise.

diff --git a/gcc/testsuite/gcc.target/nvptx/__builtin_alloca_0-1-O0.c b/gcc/testsuite/gcc.target/nvptx/__builtin_alloca_0-1-O0.c
new file mode 100644 (file)
index 0000000..8c00a66
--- /dev/null
+++ b/gcc/testsuite/gcc.target/nvptx/__builtin_alloca_0-1-O0.c
@@ -0,0 +1,37 @@
+/* Document what we run into for '__builtin_alloca(0)'.  */
+
+/* { dg-do compile }
+   TODO We can't 'assemble' this -- it's invalid PTX code.  */
+/* { dg-options {-O0 -mno-soft-stack} } */
+/* { dg-additional-options -save-temps } */
+/* { dg-final { check-function-bodies {** } {} } } */
+
+void sink(void *);
+
+void f(void)
+{
+  sink(__builtin_alloca(0));
+}
+/*
+** f:
+** .visible .func f
+** {
+**     \.reg\.u64 (%r[0-9]+);
+**     \.reg\.u64 (%r[0-9]+);
+**             mov\.u64        \1, %stack;
+**             mov\.u64        \2, \1;
+**     {
+**             \.param\.u64 %out_arg1;
+**             st\.param\.u64 \[%out_arg1\], \2;
+**             call sink, \(%out_arg1\);
+**     }
+**     ret;
+*/
+
+/* '%stack' is 'VIRTUAL_STACK_DYNAMIC_REGNUM', 'virtual_stack_dynamic_rtx'.
+   For '__builtin_alloca (0)', we get to
+   'gcc/explow.cc:allocate_dynamic_stack_space', where 'addr' gets set to
+   'virtual_stack_dynamic_rtx', 'size == const0_rtx', therefore 'return addr;',
+   which gets us '%stack' -- undefined (TODO).
+
+   { dg-final { scan-assembler-not {%stack} { xfail *-*-* } } } */

diff --git a/gcc/testsuite/gcc.target/nvptx/__builtin_alloca_0-1-O1.c b/gcc/testsuite/gcc.target/nvptx/__builtin_alloca_0-1-O1.c
new file mode 100644 (file)
index 0000000..2d61065
--- /dev/null
+++ b/gcc/testsuite/gcc.target/nvptx/__builtin_alloca_0-1-O1.c
@@ -0,0 +1,33 @@
+/* Document what we run into for '__builtin_alloca(0)'.  */
+
+/* { dg-do compile }
+   TODO We can't 'assemble' this -- it's invalid PTX code.  */
+/* { dg-options {-O1 -mno-soft-stack} } */
+/* { dg-additional-options -save-temps } */
+/* { dg-final { check-function-bodies {** } {} } } */
+
+void sink(void *);
+
+void f(void)
+{
+  sink(__builtin_alloca(0));
+}
+/*
+** f:
+** .visible .func f
+** {
+**     {
+**             \.param\.u64 %out_arg1;
+**             st\.param\.u64 \[%out_arg1\], %stack;
+**             call sink, \(%out_arg1\);
+**     }
+**     ret;
+*/
+
+/* '%stack' is 'VIRTUAL_STACK_DYNAMIC_REGNUM', 'virtual_stack_dynamic_rtx'.
+   For '__builtin_alloca (0)', we get to
+   'gcc/explow.cc:allocate_dynamic_stack_space', where 'addr' gets set to
+   'virtual_stack_dynamic_rtx', 'size == const0_rtx', therefore 'return addr;',
+   which gets us '%stack' -- undefined (TODO).
+
+   { dg-final { scan-assembler-not {%stack} { xfail *-*-* } } } */