[PATCH 1/2] testsuite: Fix analyzer errors for newlib-errno

[Hans-Peter Nilsson <hp@axis.com>]

Ok to commit?
-- >8 --
Investigating analyzer tesstsuite errors for cris-elf.  The same are
seen for pru-elf according to posts to gcc-testresults@.

For glibc, errno is #defined as:
 extern int *__errno_location (void) __THROW __attribute_const__;
 # define errno (*__errno_location ())
while for newlib in its default configuration, it's:
 #define errno (*__errno())
 extern int *__errno (void);

The critical difference is that __attribute__ ((__const__)),
where glibc says that the caller will see the same value on
all calls (from the same context; read: same thread).  I'm
not sure the absence of __attribute__ ((__const__)) for the
newlib definition is deliberate, but I guess it can.
Either way, without the "const" attribute, it can't be known
that the same location will be returned the next time, so
analyzer-tests that depend the value being known it should
see UNKNOWN rather than TRUE, that's why the deliberate
check for UNKNOWN rather than xfailing the test.

For isatty-1.c, it's the same problem, but here it'd be
unweildy with the extra dg-lines, so better just skip it for
newlib targets.

testsuite:
	* gcc.dg/analyzer/call-summaries-errno.c: Expect UNKNOWN
	for newlib after having set errno.
	* gcc.dg/analyzer/errno-1.c: Ditto.
	* gcc.dg/analyzer/isatty-1.c: Skip for newlib targets.
---
 gcc/testsuite/gcc.dg/analyzer/call-summaries-errno.c | 3 ++-
 gcc/testsuite/gcc.dg/analyzer/errno-1.c              | 3 ++-
 gcc/testsuite/gcc.dg/analyzer/isatty-1.c             | 2 +-
 3 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/gcc/testsuite/gcc.dg/analyzer/call-summaries-errno.c b/gcc/testsuite/gcc.dg/analyzer/call-summaries-errno.c
index e4333b30bb77..cf4d9f7141e4 100644
--- a/gcc/testsuite/gcc.dg/analyzer/call-summaries-errno.c
+++ b/gcc/testsuite/gcc.dg/analyzer/call-summaries-errno.c
@@ -13,5 +13,6 @@ void test_sets_errno (int y)
   sets_errno (y);
   sets_errno (y);
 
-  __analyzer_eval (errno == y); /* { dg-warning "TRUE" } */  
+  __analyzer_eval (errno == y); /* { dg-warning "TRUE" "errno is at a constant location" { target { ! newlib } } } */
+  /* { dg-warning "UNKNOWN" "errno is not known to be at a constant location" { target { newlib } } .-1 } */
 }
diff --git a/gcc/testsuite/gcc.dg/analyzer/errno-1.c b/gcc/testsuite/gcc.dg/analyzer/errno-1.c
index 6b9d28c10799..af0cc3d52a36 100644
--- a/gcc/testsuite/gcc.dg/analyzer/errno-1.c
+++ b/gcc/testsuite/gcc.dg/analyzer/errno-1.c
@@ -17,7 +17,8 @@ void test_storing_to_errno (int val)
 {
   __analyzer_eval (errno == val); /* { dg-warning "UNKNOWN" } */
   errno = val;
-  __analyzer_eval (errno == val); /* { dg-warning "TRUE" } */
+  __analyzer_eval (errno == val); /* { dg-warning "TRUE" "errno is at a constant location" { target { ! newlib } } } */
+  /* { dg-warning "UNKNOWN" "errno is not known to be at a constant location" { target { newlib } } .-1 } */
   external_fn ();
   __analyzer_eval (errno == val); /* { dg-warning "UNKNOWN" } */  
 }
diff --git a/gcc/testsuite/gcc.dg/analyzer/isatty-1.c b/gcc/testsuite/gcc.dg/analyzer/isatty-1.c
index 389d2cdf3f18..450a7d71990d 100644
--- a/gcc/testsuite/gcc.dg/analyzer/isatty-1.c
+++ b/gcc/testsuite/gcc.dg/analyzer/isatty-1.c
@@ -1,4 +1,4 @@
-/* { dg-skip-if "" { powerpc*-*-aix* } } */
+/* { dg-skip-if "" { powerpc*-*-aix* || newlib } } */
 
 #include <errno.h>
 #include "analyzer-decls.h"
-- 
2.30.2