nvptx: Disable effective-target 'freestanding'

After 2014's commit 157e859ffe3b5d43db1e19475711c1a3d21ab57a "remove picochip",
the effective-target 'freestanding' (later) was only ever used for nvptx.
However, the relevant I/O library functions have long been implemented in nvptx
newlib.

These test cases generally PASS, just a few need to get XFAILed; see
<https://docs.nvidia.com/cuda/ptx-writers-guide-to-interoperability/#system-calls>,
and then supposedly
<https://docs.nvidia.com/cuda/cuda-c-programming-guide/#formatted-output> for
description of the non-standard PTX 'vprintf' return value:

> Unlike the C-standard 'printf()', which returns the number of characters
> printed, CUDA's 'printf()' returns the number of arguments parsed. If no
> arguments follow the format string, 0 is returned. If the format string is
> NULL, -1 is returned. If an internal error occurs, -2 is returned.

(I've tried a few variants to confirm that PTX 'vprintf' -- which supposedly is
underlying the CUDA 'printf' -- is what's implementing this behavior.)
Probably, we ought to fix that up in nvptx newlib.

	gcc/testsuite/
	* gcc.c-torture/execute/printf-1.c: XFAIL for nvptx.
	* gcc.c-torture/execute/printf-chk-1.c: Likewise.
	* gcc.c-torture/execute/vprintf-1.c: Likewise.
	* gcc.c-torture/execute/vprintf-chk-1.c: Likewise.
	* lib/target-supports.exp (check_effective_target_freestanding):
	Disable for nvptx.

5 files changed, 4 insertions, 3 deletions

diff --git a/gcc/testsuite/gcc.c-torture/execute/printf-1.c b/gcc/testsuite/gcc.c-torture/execute/printf-1.c
index 654e627..e120136 100644
--- a/gcc/testsuite/gcc.c-torture/execute/printf-1.c
+++ b/gcc/testsuite/gcc.c-torture/execute/printf-1.c
@@ -1,4 +1,5 @@
 /* { dg-skip-if "requires io" { freestanding } }  */
+/* { dg-xfail-run-if {unexpected PTX 'vprintf' return value} { nvptx-*-* } } */
 
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/gcc/testsuite/gcc.c-torture/execute/printf-chk-1.c b/gcc/testsuite/gcc.c-torture/execute/printf-chk-1.c
index aab4306..6418957 100644
--- a/gcc/testsuite/gcc.c-torture/execute/printf-chk-1.c
+++ b/gcc/testsuite/gcc.c-torture/execute/printf-chk-1.c
@@ -1,4 +1,5 @@
 /* { dg-skip-if "requires io" { freestanding } }  */
+/* { dg-xfail-run-if {unexpected PTX 'vprintf' return value} { nvptx-*-* } } */
 
 #include <stdio.h>
 #include <stdlib.h>
diff --git a/gcc/testsuite/gcc.c-torture/execute/vprintf-1.c b/gcc/testsuite/gcc.c-torture/execute/vprintf-1.c
index 259397e..0fb1ade 100644
--- a/gcc/testsuite/gcc.c-torture/execute/vprintf-1.c
+++ b/gcc/testsuite/gcc.c-torture/execute/vprintf-1.c
@@ -1,4 +1,5 @@
 /* { dg-skip-if "requires io" { freestanding } }  */
+/* { dg-xfail-run-if {unexpected PTX 'vprintf' return value} { nvptx-*-* } } */
 
 #ifndef test
 #include <stdio.h>
diff --git a/gcc/testsuite/gcc.c-torture/execute/vprintf-chk-1.c b/gcc/testsuite/gcc.c-torture/execute/vprintf-chk-1.c
index 04ecc4d..7ea3617 100644
--- a/gcc/testsuite/gcc.c-torture/execute/vprintf-chk-1.c
+++ b/gcc/testsuite/gcc.c-torture/execute/vprintf-chk-1.c
@@ -1,4 +1,5 @@
 /* { dg-skip-if "requires io" { freestanding } }  */
+/* { dg-xfail-run-if {unexpected PTX 'vprintf' return value} { nvptx-*-* } } */
 
 #ifndef test
 #include <stdio.h>
diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index 459af8e..1c9bbf6 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -859,9 +859,6 @@ proc check_profiling_available { test_what } {
 # in Section 4 of C99 standard. Effectively, it is a target which supports no
 # extra headers or libraries other than what is considered essential.
 proc check_effective_target_freestanding { } {
-    if { [istarget nvptx-*-*] } {
-	return 1
-    }
     return 0
 }