analyzer: fix ICE on escaped unknown pointers [PR96611]

PR analyzer/96611 reports an ICE within the handling for unknown
functions, when passing a pointer to something accessed via a
global pointer, after an unknown function has already been called.

The first unknown function leads to the store being flagged, so
the access to the global pointer leads to (*unknown_svalue) for
the base region of the argument to the 2nd function, and thus
*unknown_svalue being reachable by the 2nd unknown function,
triggering an assertion failure.

Handle this case by rejecting attempts to get a cluster for
the unknown pointer, fixing the ICE.

gcc/analyzer/ChangeLog:
	PR analyzer/96611
	* store.cc (store::mark_as_escaped): Reject attempts to
	get a cluster for an unknown pointer.

gcc/testsuite/ChangeLog:
	PR analyzer/96611
	* gcc.dg/analyzer/pr96611.c: New test.

1 files changed, 14 insertions, 0 deletions

diff --git a/gcc/testsuite/gcc.dg/analyzer/pr96611.c b/gcc/testsuite/gcc.dg/analyzer/pr96611.c
new file mode 100644
index 00000000000..4f7502361cb
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/analyzer/pr96611.c
@@ -0,0 +1,14 @@
+struct s { int a; } *ptr;
+void unknown_int_ptr (int *);
+void unknown_void (void);
+
+void test_1 ()
+{
+  unknown_int_ptr (&ptr->a);
+}
+
+void test_2 ()
+{
+  unknown_void ();
+  unknown_int_ptr (&ptr->a);
+}