Import of old SSLeay release: SSLeay 0.8.1b

bugs/dggccbug.c

@@ -0,0 +1,45 @@
+/* NOCW */
+/* dggccbug.c */
+/* bug found by Eric Young (eay@cryptsoft.com) - May 1995 */
+
+#include <stdio.h>
+
+/* There is a bug in
+ * gcc version 2.5.8 (88open OCS/BCS, DG-2.5.8.3, Oct 14 1994)
+ * as shipped with DGUX 5.4R3.10 that can be bypassed by defining
+ * DG_GCC_BUG in my code.
+ * The bug manifests itself by the vaule of a pointer that is
+ * used only by reference, not having it's value change when it is used
+ * to check for exiting the loop.  Probably caused by there being 2
+ * copies of the valiable, one in a register and one being an address
+ * that is passed. */
+
+/* compare the out put from
+ * gcc dggccbug.c; ./a.out
+ * and
+ * gcc -O dggccbug.c; ./a.out
+ * compile with -DFIXBUG to remove the bug when optimising.
+ */
+
+void inc(a)
+int *a;
+	{
+	(*a)++;
+	}
+
+main()
+	{
+	int p=0;
+#ifdef FIXBUG
+	int dummy;
+#endif
+
+	while (p<3)
+		{
+		fprintf(stderr,"%08X\n",p);
+		inc(&p);
+#ifdef FIXBUG
+		dummy+=p;
+#endif
+		}
+	}