#define __typecheck(x, y) \
(!!(sizeof((typeof(x) *)1 == (typeof(y) *)1)))
-/* is_signed_type() isn't a constexpr for pointer types */
-#define __is_signed(x) \
- __builtin_choose_expr(__is_constexpr(is_signed_type(typeof(x))), \
- is_signed_type(typeof(x)), 0)
+/*
+ * __sign_use for integer expressions:
+ * bit #0 set if ok for unsigned comparisons
+ * bit #1 set if ok for signed comparisons
+ *
+ * In particular, statically non-negative signed integer
+ * expressions are ok for both.
+ *
+ * NOTE! Unsigned types smaller than 'int' are implicitly
+ * converted to 'int' in expressions, and are accepted for
+ * signed conversions for now. This is debatable.
+ *
+ * Note that 'x' is the original expression, and 'ux' is
+ * the unique variable that contains the value.
+ *
+ * We use 'ux' for pure type checking, and 'x' for when
+ * we need to look at the value (but without evaluating
+ * it for side effects! Careful to only ever evaluate it
+ * with sizeof() or __builtin_constant_p() etc).
+ *
+ * Pointers end up being checked by the normal C type
+ * rules at the actual comparison, and these expressions
+ * only need to be careful to not cause warnings for
+ * pointer use.
+ */
+#define __signed_type_use(x,ux) (2+__is_nonneg(x,ux))
+#define __unsigned_type_use(x,ux) (1+2*(sizeof(ux)<4))
+#define __sign_use(x,ux) (is_signed_type(typeof(ux))? \
+ __signed_type_use(x,ux):__unsigned_type_use(x,ux))
+
+/*
+ * To avoid warnings about casting pointers to integers
+ * of different sizes, we need that special sign type.
+ *
+ * On 64-bit we can just always use 'long', since any
+ * integer or pointer type can just be cast to that.
+ *
+ * This does not work for 128-bit signed integers since
+ * the cast would truncate them, but we do not use s128
+ * types in the kernel (we do use 'u128', but they will
+ * be handled by the !is_signed_type() case).
+ *
+ * NOTE! The cast is there only to avoid any warnings
+ * from when values that aren't signed integer types.
+ */
+#ifdef CONFIG_64BIT
+ #define __signed_type(ux) long
+#else
+ #define __signed_type(ux) typeof(__builtin_choose_expr(sizeof(ux)>4,1LL,1L))
+#endif
+#define __is_nonneg(x,ux) statically_true((__signed_type(ux))(x)>=0)
-/* True for a non-negative signed int constant */
-#define __is_noneg_int(x) \
- (__builtin_choose_expr(__is_constexpr(x) && __is_signed(x), x, -1) >= 0)
+#define __types_ok(x,y,ux,uy) \
+ (__sign_use(x,ux) & __sign_use(y,uy))
-#define __types_ok(x, y, ux, uy) \
- (__is_signed(ux) == __is_signed(uy) || \
- __is_signed((ux) + 0) == __is_signed((uy) + 0) || \
- __is_noneg_int(x) || __is_noneg_int(y))
+#define __types_ok3(x,y,z,ux,uy,uz) \
+ (__sign_use(x,ux) & __sign_use(y,uy) & __sign_use(z,uz))
#define __cmp_op_min <
#define __cmp_op_max >
#define __careful_cmp_once(op, x, y, ux, uy) ({ \
__auto_type ux = (x); __auto_type uy = (y); \
- static_assert(__types_ok(x, y, ux, uy), \
- #op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \
+ BUILD_BUG_ON_MSG(!__types_ok(x,y,ux,uy), \
+ #op"("#x", "#y") signedness error"); \
__cmp(op, ux, uy); })
#define __careful_cmp(op, x, y) \
static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), \
(lo) <= (hi), true), \
"clamp() low limit " #lo " greater than high limit " #hi); \
- static_assert(__types_ok(uval, lo, uval, ulo), "clamp() 'lo' signedness error"); \
- static_assert(__types_ok(uval, hi, uval, uhi), "clamp() 'hi' signedness error"); \
+ BUILD_BUG_ON_MSG(!__types_ok3(val,lo,hi,uval,ulo,uhi), \
+ "clamp("#val", "#lo", "#hi") signedness error"); \
__clamp(uval, ulo, uhi); })
#define __careful_clamp(val, lo, hi) \