alloca fails in loops

[r15466]

ir/be/test/fehler59.c

+#include <alloca.h>
+
+int main()
+{
+	char *b1 = alloca(13);
+	int i;
+
+	for(i = 0; i < 5; ++i) {
+		char *bfs = alloca(24);
+		printf("Offset: %d\n", bfs - b1);
+	}
+
+	return 0;
+}