add extra underscore to _bzero, add a test for bzero/memset

test/val/bzero.c

@@ -0,0 +1,51 @@
+
+// test if memset and bzero work as expected after optimizations
+
+#include <string.h>
+
+char s1[10] = { 1,2,3,4,5,6,7,8,9,10 };
+char r1[10] = { 0,0,0,0,0,6,7,8,9,10 };
+
+char s2[10] = { 1,2,3,4,5,6,7,8,9,10 };
+char r2[10] = { 0,0,0,0,0,0,7,8,9,10 };
+
+char s3[10] = { 1,2,3,4,5,6,7,8,9,10 };
+char r3[10] = { 0,0,0,0,0,0,0,8,9,10 };
+
+char *p1, *p2, *p3;
+
+int res = 0;
+
+int main(void)
+{
+    /* regular bzero */
+    bzero(s1, 5);
+    p1 = __AX__; /* this works because bzero jumps into memset */
+    /* this gets converted to __bzero */
+    p2 = memset(s2, 0, 6);
+    /* call internal __bzero (we should not do this in real code) */
+    p3 = __bzero(s3, 7);
+
+    /* check the results */
+    if (memcmp(s1, r1, 10) != 0) {
+        res++;
+    }
+    if (memcmp(s2, r2, 10) != 0) {
+        res++;
+    }
+    if (memcmp(s3, r3, 10) != 0) {
+        res++;
+    }
+
+    if (p1 != s1) {
+        res++;
+    }
+    if (p2 != s2) {
+        res++;
+    }
+    if (p3 != s3) {
+        res++;
+    }
+
+    return res;
+}