| Message ID | 0ca26166dd2a4ff5a674b84704ff1517@AcuMS.aculab.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | minmax: Optimise to reduce .i line length. | expand |
The defines for clamp() have got separated, move togther for readability.
Update description of signedness check.
Signed-off-by: David Laight <david.laight@aculab.com>
---
include/linux/minmax.h | 120 +++++++++++++++++++----------------------
1 file changed, 56 insertions(+), 64 deletions(-)
diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 2ec559284a9f..63c45865b48a 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -57,26 +57,6 @@
__cmp(op, x, y), \
__cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))
-#define __clamp(val, lo, hi) \
- ((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val)))
-
-#define __clamp_once(val, lo, hi, unique_val, unique_lo, unique_hi) ({ \
- typeof(val) unique_val = (val); \
- typeof(lo) unique_lo = (lo); \
- typeof(hi) unique_hi = (hi); \
- 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(val, lo), "clamp() 'lo' signedness error"); \
- static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error"); \
- __clamp(unique_val, unique_lo, unique_hi); })
-
-#define __careful_clamp(val, lo, hi) ({ \
- __builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)), \
- __clamp(val, lo, hi), \
- __clamp_once(val, lo, hi, __UNIQUE_ID(__val), \
- __UNIQUE_ID(__lo), __UNIQUE_ID(__hi))); })
-
/**
* min - return minimum of two values of the same or compatible types
* @x: first value
@@ -124,6 +104,22 @@
*/
#define max3(x, y, z) max((typeof(x))max(x, y), z)
+/**
+ * min_t - return minimum of two values, using the specified type
+ * @type: data type to use
+ * @x: first value
+ * @y: second value
+ */
+#define min_t(type, x, y) __careful_cmp(min, (type)(x), (type)(y))
+
+/**
+ * max_t - return maximum of two values, using the specified type
+ * @type: data type to use
+ * @x: first value
+ * @y: second value
+ */
+#define max_t(type, x, y) __careful_cmp(max, (type)(x), (type)(y))
+
/**
* min_not_zero - return the minimum that is _not_ zero, unless both are zero
* @x: value1
@@ -134,39 +130,60 @@
typeof(y) __y = (y); \
__x == 0 ? __y : ((__y == 0) ? __x : min(__x, __y)); })
+#define __clamp(val, lo, hi) \
+ ((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val)))
+
+#define __clamp_once(val, lo, hi, unique_val, unique_lo, unique_hi) ({ \
+ typeof(val) unique_val = (val); \
+ typeof(lo) unique_lo = (lo); \
+ typeof(hi) unique_hi = (hi); \
+ 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(val, lo), "clamp() 'lo' signedness error"); \
+ static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error"); \
+ __clamp(unique_val, unique_lo, unique_hi); })
+
+#define __careful_clamp(val, lo, hi) ({ \
+ __builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)), \
+ __clamp(val, lo, hi), \
+ __clamp_once(val, lo, hi, __UNIQUE_ID(__val), \
+ __UNIQUE_ID(__lo), __UNIQUE_ID(__hi))); })
+
/**
* clamp - return a value clamped to a given range with strict typechecking
* @val: current value
* @lo: lowest allowable value
* @hi: highest allowable value
*
- * This macro does strict typechecking of @lo/@hi to make sure they are of the
- * same type as @val. See the unnecessary pointer comparisons.
+ * This macro checks that @val, @lo and @hi have the same signedness.
*/
#define clamp(val, lo, hi) __careful_clamp(val, lo, hi)
-/*
- * ..and if you can't take the strict
- * types, you can specify one yourself.
- *
- * Or not use min/max/clamp at all, of course.
- */
-
/**
- * min_t - return minimum of two values, using the specified type
- * @type: data type to use
- * @x: first value
- * @y: second value
+ * clamp_t - return a value clamped to a given range using a given type
+ * @type: the type of variable to use
+ * @val: current value
+ * @lo: minimum allowable value
+ * @hi: maximum allowable value
+ *
+ * This macro does no typechecking and uses temporary variables of type
+ * @type to make all the comparisons.
*/
-#define min_t(type, x, y) __careful_cmp(min, (type)(x), (type)(y))
+#define clamp_t(type, val, lo, hi) __careful_clamp((type)(val), (type)(lo), (type)(hi))
/**
- * max_t - return maximum of two values, using the specified type
- * @type: data type to use
- * @x: first value
- * @y: second value
+ * clamp_val - return a value clamped to a given range using val's type
+ * @val: current value
+ * @lo: minimum allowable value
+ * @hi: maximum allowable value
+ *
+ * This macro does no typechecking and uses temporary variables of whatever
+ * type the input argument @val is. This is useful when @val is an unsigned
+ * type and @lo and @hi are literals that will otherwise be assigned a signed
+ * integer type.
*/
-#define max_t(type, x, y) __careful_cmp(max, (type)(x), (type)(y))
+#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
/*
* Do not check the array parameter using __must_be_array().
@@ -211,31 +228,6 @@
*/
#define max_array(array, len) __minmax_array(max, array, len)
-/**
- * clamp_t - return a value clamped to a given range using a given type
- * @type: the type of variable to use
- * @val: current value
- * @lo: minimum allowable value
- * @hi: maximum allowable value
- *
- * This macro does no typechecking and uses temporary variables of type
- * @type to make all the comparisons.
- */
-#define clamp_t(type, val, lo, hi) __careful_clamp((type)(val), (type)(lo), (type)(hi))
-
-/**
- * clamp_val - return a value clamped to a given range using val's type
- * @val: current value
- * @lo: minimum allowable value
- * @hi: maximum allowable value
- *
- * This macro does no typechecking and uses temporary variables of whatever
- * type the input argument @val is. This is useful when @val is an unsigned
- * type and @lo and @hi are literals that will otherwise be assigned a signed
- * integer type.
- */
-#define clamp_val(val, lo, hi) clamp_t(typeof(val), val, lo, hi)
-
static inline bool in_range64(u64 val, u64 start, u64 len)
{
return (val - start) < len;
The wrapper just adds two more lines of error output when the test fails.
Signed-off-by: David Laight <david.laight@aculab.com>
---
include/linux/minmax.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 63c45865b48a..900eec7a28e5 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -48,7 +48,7 @@
#define __cmp_once(op, x, y, unique_x, unique_y) ({ \
typeof(x) unique_x = (x); \
typeof(y) unique_y = (y); \
- static_assert(__types_ok(x, y), \
+ _Static_assert(__types_ok(x, y), \
#op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \
__cmp(op, unique_x, unique_y); })
@@ -137,11 +137,11 @@
typeof(val) unique_val = (val); \
typeof(lo) unique_lo = (lo); \
typeof(hi) unique_hi = (hi); \
- static_assert(__builtin_choose_expr(__is_constexpr((lo) > (hi)), \
+ _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(val, lo), "clamp() 'lo' signedness error"); \
- static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error"); \
+ _Static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error"); \
+ _Static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error"); \
__clamp(unique_val, unique_lo, unique_hi); })
#define __careful_clamp(val, lo, hi) ({ \
It is enough to check that both 'x' and 'y' are valid for either
a signed compare or an unsigned compare.
For unsigned they must be an unsigned type or a positive constant.
For signed they must be signed after unsigned char/short are promoted.
The predicate for _Static_assert() only needs to be a compile-time
constant not a constant integeger expression.
In particular the short-circuit evaluation of || && ?: can be used
to avoid the non-constantness of (pointer_type)1 in is_signed_type().
The '+ 0' in '(x) + 0 > = 0' is there to convert 'bool' to 'int'
and avoid a compiler warning because max() gets used for 'bool'
in one place (a very expensive 'or').
(The code is optimised away by two earlier checks - but the compiler
still bleats.)
Signed-off-by: David Laight <david.laight@aculab.com>
---
include/linux/minmax.h | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)
diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 900eec7a28e5..c32b4b40ce01 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -8,7 +8,7 @@
#include <linux/types.h>
/*
- * min()/max()/clamp() macros must accomplish three things:
+ * min()/max()/clamp() macros must accomplish several things:
*
* - Avoid multiple evaluations of the arguments (so side-effects like
* "x++" happen only once) when non-constant.
@@ -26,19 +26,17 @@
#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)
+/* Allow unsigned compares against non-negative signed constants. */
+#define __is_ok_unsigned(x) \
+ (is_unsigned_type(typeof(x)) || (__is_constexpr(x) ? (x) + 0 >= 0 : 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)
+/* Check for signed after promoting unsigned char/short to int */
+#define __is_ok_signed(x) is_signed_type(typeof((x) + 0))
-#define __types_ok(x, y) \
- (__is_signed(x) == __is_signed(y) || \
- __is_signed((x) + 0) == __is_signed((y) + 0) || \
- __is_noneg_int(x) || __is_noneg_int(y))
+/* Allow if both x and y are valid for either signed or unsigned compares. */
+#define __types_ok(x, y) \
+ ((__is_ok_signed(x) && __is_ok_signed(y)) || \
+ (__is_ok_unsigned(x) && __is_ok_unsigned(y)))
#define __cmp_op_min <
#define __cmp_op_max >
Provided __COUNTER__ is passed through an extra #define it can be pasted
onto multiple local variables to give unique names.
This saves having 3 __UNIQUE_ID() for #defines with three locals and
look less messy in general.
Stop the umin()/umax() lines being overlong by factoring out the
zero-extension logic.
Signed-off-by: David Laight <david.laight@aculab.com>
---
include/linux/minmax.h | 48 +++++++++++++++++++++---------------------
1 file changed, 24 insertions(+), 24 deletions(-)
diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index c32b4b40ce01..8ee003d8abaf 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -8,7 +8,7 @@
#include <linux/types.h>
/*
- * min()/max()/clamp() macros must accomplish several things:
+ * min()/max()/clamp() macros must accomplish three things:
*
* - Avoid multiple evaluations of the arguments (so side-effects like
* "x++" happen only once) when non-constant.
@@ -43,31 +43,31 @@
#define __cmp(op, x, y) ((x) __cmp_op_##op (y) ? (x) : (y))
-#define __cmp_once(op, x, y, unique_x, unique_y) ({ \
- typeof(x) unique_x = (x); \
- typeof(y) unique_y = (y); \
- _Static_assert(__types_ok(x, y), \
+#define __cmp_once(op, x, y, uniq) ({ \
+ typeof(x) __x_##uniq = (x); \
+ typeof(y) __y_##uniq = (y); \
+ _Static_assert(__types_ok(x, y), \
#op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \
- __cmp(op, unique_x, unique_y); })
+ __cmp(op, __x_##uniq, __y_##uniq); })
-#define __careful_cmp(op, x, y) \
+#define __careful_cmp(op, x, y, uniq) \
__builtin_choose_expr(__is_constexpr((x) - (y)), \
__cmp(op, x, y), \
- __cmp_once(op, x, y, __UNIQUE_ID(__x), __UNIQUE_ID(__y)))
+ __cmp_once(op, x, y, uniq))
/**
* min - return minimum of two values of the same or compatible types
* @x: first value
* @y: second value
*/
-#define min(x, y) __careful_cmp(min, x, y)
+#define min(x, y) __careful_cmp(min, x, y, __COUNTER__)
/**
* max - return maximum of two values of the same or compatible types
* @x: first value
* @y: second value
*/
-#define max(x, y) __careful_cmp(max, x, y)
+#define max(x, y) __careful_cmp(max, x, y, __COUNTER__)
/**
* umin - return minimum of two non-negative values
@@ -75,8 +75,9 @@
* @x: first value
* @y: second value
*/
+#define __zero_extend(x) ((x) + 0u + 0ul + 0ull)
#define umin(x, y) \
- __careful_cmp(min, (x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull)
+ __careful_cmp(min, __zero_extend(x), _zero_extend(y), __COUNTER__)
/**
* umax - return maximum of two non-negative values
@@ -84,7 +85,7 @@
* @y: second value
*/
#define umax(x, y) \
- __careful_cmp(max, (x) + 0u + 0ul + 0ull, (y) + 0u + 0ul + 0ull)
+ __careful_cmp(max, __zero_extend(x), _zero_extend(y), __COUNTER__)
/**
* min3 - return minimum of three values
@@ -108,7 +109,7 @@
* @x: first value
* @y: second value
*/
-#define min_t(type, x, y) __careful_cmp(min, (type)(x), (type)(y))
+#define min_t(type, x, y) __careful_cmp(min, (type)(x), (type)(y), __COUNTER__)
/**
* max_t - return maximum of two values, using the specified type
@@ -116,7 +117,7 @@
* @x: first value
* @y: second value
*/
-#define max_t(type, x, y) __careful_cmp(max, (type)(x), (type)(y))
+#define max_t(type, x, y) __careful_cmp(max, (type)(x), (type)(y), __COUNTER__)
/**
* min_not_zero - return the minimum that is _not_ zero, unless both are zero
@@ -131,22 +132,21 @@
#define __clamp(val, lo, hi) \
((val) >= (hi) ? (hi) : ((val) <= (lo) ? (lo) : (val)))
-#define __clamp_once(val, lo, hi, unique_val, unique_lo, unique_hi) ({ \
- typeof(val) unique_val = (val); \
- typeof(lo) unique_lo = (lo); \
- typeof(hi) unique_hi = (hi); \
+#define __clamp_once(val, lo, hi, uniq) ({ \
+ typeof(val) __val_##uniq = (val); \
+ typeof(lo) __lo_##uniq = (lo); \
+ typeof(hi) __hi_##uniq = (hi); \
_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(val, lo), "clamp() 'lo' signedness error"); \
_Static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error"); \
- __clamp(unique_val, unique_lo, unique_hi); })
+ __clamp(__val_##uniq, __lo_##uniq, __hi_##uniq); })
-#define __careful_clamp(val, lo, hi) ({ \
+#define __careful_clamp(val, lo, hi, uniq) ({ \
__builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)), \
__clamp(val, lo, hi), \
- __clamp_once(val, lo, hi, __UNIQUE_ID(__val), \
- __UNIQUE_ID(__lo), __UNIQUE_ID(__hi))); })
+ __clamp_once(val, lo, hi, uniq)); })
/**
* clamp - return a value clamped to a given range with strict typechecking
@@ -156,7 +156,7 @@
*
* This macro checks that @val, @lo and @hi have the same signedness.
*/
-#define clamp(val, lo, hi) __careful_clamp(val, lo, hi)
+#define clamp(val, lo, hi) __careful_clamp(val, lo, hi, __COUNTER__)
/**
* clamp_t - return a value clamped to a given range using a given type
@@ -168,7 +168,7 @@
* This macro does no typechecking and uses temporary variables of type
* @type to make all the comparisons.
*/
-#define clamp_t(type, val, lo, hi) __careful_clamp((type)(val), (type)(lo), (type)(hi))
+#define clamp_t(type, val, lo, hi) clamp((type)(val), (type)(lo), (type)(hi))
/**
* clamp_val - return a value clamped to a given range using val's type
There is no need to do the signedness/type check when the arguments
are being cast to a fixed type.
So move the check out of __xxx_once() into __careful_xxx().
Signed-off-by: David Laight <david.laight@aculab.com>
---
include/linux/minmax.h | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 8ee003d8abaf..111c52a14fe5 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -46,14 +46,14 @@
#define __cmp_once(op, x, y, uniq) ({ \
typeof(x) __x_##uniq = (x); \
typeof(y) __y_##uniq = (y); \
- _Static_assert(__types_ok(x, y), \
- #op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \
__cmp(op, __x_##uniq, __y_##uniq); })
#define __careful_cmp(op, x, y, uniq) \
__builtin_choose_expr(__is_constexpr((x) - (y)), \
__cmp(op, x, y), \
- __cmp_once(op, x, y, uniq))
+ ({ _Static_assert(__types_ok(x, y), \
+ #op "(" #x ", " #y ") signedness error, fix types or consider u" #op "() before " #op "_t()"); \
+ __cmp_once(op, x, y, uniq); }))
/**
* min - return minimum of two values of the same or compatible types
@@ -139,14 +139,14 @@
_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(val, lo), "clamp() 'lo' signedness error"); \
- _Static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error"); \
__clamp(__val_##uniq, __lo_##uniq, __hi_##uniq); })
-#define __careful_clamp(val, lo, hi, uniq) ({ \
+#define __careful_clamp(val, lo, hi, uniq) \
__builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)), \
__clamp(val, lo, hi), \
- __clamp_once(val, lo, hi, uniq)); })
+ ({ _Static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error"); \
+ _Static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error"); \
+ __clamp_once(val, lo, hi, uniq); }))
/**
* clamp - return a value clamped to a given range with strict typechecking
Nothing requires that clamp() return a constant expression.
The logic to do so significantly increases the .i file.
Remove the check and directly expand __clamp_once() from clamp_t()
since the type check can't fail.
Signed-off-by: David Laight <david.laight@aculab.com>
---
include/linux/minmax.h | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 111c52a14fe5..5c7fce76abe5 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -141,12 +141,10 @@
"clamp() low limit " #lo " greater than high limit " #hi); \
__clamp(__val_##uniq, __lo_##uniq, __hi_##uniq); })
-#define __careful_clamp(val, lo, hi, uniq) \
- __builtin_choose_expr(__is_constexpr((val) - (lo) + (hi)), \
- __clamp(val, lo, hi), \
- ({ _Static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error"); \
- _Static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error"); \
- __clamp_once(val, lo, hi, uniq); }))
+#define __careful_clamp(val, lo, hi, uniq) ({ \
+ _Static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error"); \
+ _Static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error"); \
+ __clamp_once(val, lo, hi, uniq); })
/**
* clamp - return a value clamped to a given range with strict typechecking
@@ -168,7 +166,9 @@
* This macro does no typechecking and uses temporary variables of type
* @type to make all the comparisons.
*/
-#define clamp_t(type, val, lo, hi) clamp((type)(val), (type)(lo), (type)(hi))
+#define __clamp_t(type, val, lo, hi, uniq) \
+ __clamp_once((type)(val), (type)(lo), (type)(hi), uniq)
+#define clamp_t(type, val, lo, hi) __clamp_t(type, val, lo, hi, __COUNTER__)
/**
* clamp_val - return a value clamped to a given range using val's type
min3() and max3() were added to optimise nested min(x, min(y, z))
sequences, bit only moved where the expansion was requiested.
Add a separate implementation for 3 argument calls.
These are never required to generate constant expressiions to
remove that logic.
Signed-off-by: David Laight <david.laight@aculab.com>
---
include/linux/minmax.h | 23 +++++++++++++++++++----
1 file changed, 19 insertions(+), 4 deletions(-)
diff --git a/include/linux/minmax.h b/include/linux/minmax.h
index 5c7fce76abe5..278a390b8a4c 100644
--- a/include/linux/minmax.h
+++ b/include/linux/minmax.h
@@ -38,6 +38,11 @@
((__is_ok_signed(x) && __is_ok_signed(y)) || \
(__is_ok_unsigned(x) && __is_ok_unsigned(y)))
+/* Check three values for min3(), max3() and clamp() */
+#define __types_ok3(x, y, z) \
+ ((__is_ok_signed(x) && __is_ok_signed(y) && __is_ok_signed(z)) || \
+ (__is_ok_unsigned(x) && __is_ok_unsigned(y) && __is_ok_unsigned(z)))
+
#define __cmp_op_min <
#define __cmp_op_max >
@@ -87,13 +92,24 @@
#define umax(x, y) \
__careful_cmp(max, __zero_extend(x), _zero_extend(y), __COUNTER__)
+#define __cmp_once3(op, x, y, z, uniq) ({ \
+ typeof(x) __x_##uniq = (x); \
+ typeof(x) __y_##uniq = (y); \
+ typeof(x) __z_##uniq = (z); \
+ __cmp(op, __cmp(op, __x_##uniq, __y_##uniq), __z_##uniq); })
+
+#define __careful_cmp3(op, x, y, z, uniq) ({ \
+ static_assert(__types_ok3(x, y, z), \
+ #op "3(" #x ", " #y ", " #z ") signedness error"); \
+ __cmp_once3(op, x, y, z, uniq); })
+
/**
* min3 - return minimum of three values
* @x: first value
* @y: second value
* @z: third value
*/
-#define min3(x, y, z) min((typeof(x))min(x, y), z)
+#define min3(x, y, z) __careful_cmp3(min, x, y, z, __COUNTER__)
/**
* max3 - return maximum of three values
@@ -101,7 +117,7 @@
* @y: second value
* @z: third value
*/
-#define max3(x, y, z) max((typeof(x))max(x, y), z)
+#define max3(x, y, z) __careful_cmp3(max, x, y, z, __COUNTER__)
/**
* min_t - return minimum of two values, using the specified type
@@ -142,8 +158,7 @@
__clamp(__val_##uniq, __lo_##uniq, __hi_##uniq); })
#define __careful_clamp(val, lo, hi, uniq) ({ \
- _Static_assert(__types_ok(val, lo), "clamp() 'lo' signedness error"); \
- _Static_assert(__types_ok(val, hi), "clamp() 'hi' signedness error"); \
+ _Static_assert(__types_ok3(val, lo, hi), "clamp() signedness error"); \
__clamp_once(val, lo, hi, uniq); })
/**
The changes to minmax.h that changed the type check to a signedness check significantly increased the length of the expansion. In some cases it has also significantly increased compile type. This is particularly noticeable for nested expansions. The fact that _Static_assert() only requires a compile time constant not a constant expression allows a lot of simplification. The other thing that complicates the expansion is the necessity of returning a constant expression from constant arguments (for VLA). I can only find a handful of places this is done. Penalising most of the code for these few cases seems 'suboptimal'. Instead I've added min_const() and max_const() for VLA and static initialisers, these check the arguments are constant to avoid misuse. Patch [9] is dependent on the earlier patches. Patch [10] isn't dependant on them. Patch [11] depends on both 9 and 10. David Laight (11): [1] minmax: Put all the clamp() definitions together [2] minmax: Use _Static_assert() instead of static_assert() [3] minmax: Simplify signedness check [4] minmax: Replace multiple __UNIQUE_ID() by directly using __COUNTER__ [5] minmax: Move the signedness check out of __cmp_once() and __clamp_once() [6] minmax: Remove 'constexpr' check from __careful_clamp() [7] minmax: minmax: Add __types_ok3() and optimise defines with 3 arguments [8] minmax: Add min_const() and max_const() [9] tree-wide: minmax: Replace all the uses of max() for array sizes with max_const(). [10] block: Use a boolean expression instead of max() on booleans [11] minmax: min() and max() don't need to return constant expressions block/blk-settings.c | 2 +- drivers/gpu/drm/amd/pm/swsmu/smu_cmn.c | 2 +- drivers/gpu/drm/drm_color_mgmt.c | 4 +- drivers/input/touchscreen/cyttsp4_core.c | 2 +- .../net/can/usb/etas_es58x/es58x_devlink.c | 2 +- fs/btrfs/tree-checker.c | 2 +- include/linux/minmax.h | 211 ++++++++++-------- lib/vsprintf.c | 4 +- net/ipv4/proc.c | 2 +- net/ipv6/proc.c | 2 +- 10 files changed, 127 insertions(+), 106 deletions(-)