Merge pull request #2345 from acqn/PtrFix

[cc65] Fixed regression on comparison to null pointer

test/val/nullptr.c

@@ -0,0 +1,71 @@
+/* Bug # - Pointer compared to null pointer constant */
+
+#include <stdio.h>
+
+unsigned failures;
+
+struct S {
+    char a[4];
+} *p;
+
+#define TEST_NULL(E) \
+    do { \
+        a = (E) == 0 && !(E); \
+        if (!a) \
+        { \
+            ++failures; \
+            printf("failed: " #E " should be null\n"); \
+        } \
+    } while(0);
+
+#define TEST_NON_NULL(E) \
+    do { \
+        a = (E) != 0 && !!(E) && (E); \
+        if (!a) \
+        { \
+            ++failures; \
+            printf("failed: " #E " should be non-null\n"); \
+        } \
+    } while(0);
+
+int main()
+{
+    int a;
+
+    /* Null pointer constant (per ISO C) compared equal to null pointer constant */
+    TEST_NULL((void*)0)
+
+    /* Null pointer compared equal to null pointer constant */
+    TEST_NULL((char*)0)
+
+    /* Null pointer obtained with -> */
+    TEST_NULL(((struct S*)0)->a)
+
+    /* Null pointer obtained with -> */
+    TEST_NULL(p->a)
+
+    /* Null pointer obtained with cast and -> */
+    TEST_NULL(((struct S*)(a = 0))->a)
+
+    /* Null pointer obtained with cast and -> */
+    TEST_NULL((a = 0, ((struct S*)a)->a))
+
+    /* Non-null pointer obtained with cast and -> */
+    TEST_NON_NULL(((struct S*)(long)(a = 0x1234))->a)
+
+    /* Non-null pointer obtained with cast and -> */
+    TEST_NON_NULL((a = 0x1234, ((struct S*)a)->a))
+
+    /* Non-null pointer obtained with cast and -> */
+    TEST_NON_NULL(((struct S*)&a)->a)
+
+    /* Non-null pointer obtained with cast and -> */
+    TEST_NON_NULL(((struct S*)&main)->a)
+
+    if (failures != 0)
+    {
+        printf("failures: %u\n", failures);
+    }
+
+    return failures;
+}