analyzer testsuite: add explode-2a.c [PR101068]

Due to a bug (PR analyzer/101068), the analyzer only explores a limited
subset of the possible paths through gcc.dg/analyzer/explode-2.c,
and this artifically helps stop this testcase from exploding.
I intend to fix this at some point, but for now, this patch adds a
revised test case which captures the effective CFG due to the bug, so
that we explicitly have test coverage for that CFG.

gcc/testsuite/ChangeLog:
	PR analyzer/101068
	* gcc.dg/analyzer/explode-2a.c: New test.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>

gcc/testsuite/gcc.dg/analyzer/explode-2a.c

@@ -0,0 +1,51 @@
+/* PR analyzer/101068.  */
+
+/* { dg-additional-options "--param analyzer-max-enodes-per-program-point=200 --param analyzer-bb-explosion-factor=50" } */
+
+#include <stdlib.h>
+
+extern int get (void);
+
+void test (void)
+{
+  void *p0, *p1, *p2, *p3;
+  /* Due to not purging constraints on SSA names within loops
+     (PR analyzer/101068), the analyzer effectively treats the original
+     explode-2.c as this code.  */
+  int a = get ();
+  int b = get ();
+  while (a)
+    {
+      switch (b)
+	{
+	default:
+	case 0:
+	  p0 = malloc (16); /* { dg-warning "leak" } */
+	  break;
+	case 1:
+	  free (p0); /* { dg-warning "double-'free' of 'p0'" "" { xfail *-*-* } } */
+	  break;
+
+	case 2:
+	  p1 = malloc (16); /* { dg-warning "leak" } */
+	  break;
+	case 3:
+	  free (p1); /* { dg-warning "double-'free' of 'p1'" "" { xfail *-*-* } } */
+	  break;
+
+	case 4:
+	  p2 = malloc (16); /* { dg-warning "leak" } */
+	  break;
+	case 5:
+	  free (p2); /* { dg-warning "double-'free' of 'p2'" "" { xfail *-*-* } } */
+	  break;
+
+	case 6:
+	  p3 = malloc (16); /* { dg-warning "leak" } */
+	  break;
+	case 7:
+	  free (p3); /* { dg-warning "double-'free' of 'p3'" "" { xfail *-*-* } } */
+	  break;
+	}
+    }
+}