| Message ID | 20241203-is_constexpr-refactor-v1-8-4e4cbaecc216@wanadoo.fr (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | compiler.h: refactor __is_constexpr() into is_const{,_true,_false}() | expand |
From: Vincent Mailhol > Sent: 02 December 2024 17:34 > > Most of the use of __is_const_expr() in i915_reg_defs.h are just to > test whether an expression is known to be true. Because those checks > are all done in a BUILD_BUG_ON_ZERO(), replace those with > is_const_true(). Another place that could use statically_true() and BUILD_BUG_ON_MSG(). David > > Replace the few other occurrences of __is_const_expr() with is_const(). > > Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr> > --- > drivers/gpu/drm/i915/i915_reg_defs.h | 47 +++++++++++++++++------------------- > 1 file changed, 22 insertions(+), 25 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_reg_defs.h b/drivers/gpu/drm/i915/i915_reg_defs.h > index e251bcc0c89f5710125bc70f07851b2cb978c89c..6ed2fb9cf506a3bd6467ba30f9d0e863d62762f3 100644 > --- a/drivers/gpu/drm/i915/i915_reg_defs.h > +++ b/drivers/gpu/drm/i915/i915_reg_defs.h > @@ -19,8 +19,7 @@ > */ > #define REG_BIT(__n) \ > ((u32)(BIT(__n) + \ > - BUILD_BUG_ON_ZERO(__is_constexpr(__n) && \ > - ((__n) < 0 || (__n) > 31)))) > + BUILD_BUG_ON_ZERO(is_const_true((__n) < 0 || (__n) > 31)))) > > /** > * REG_BIT8() - Prepare a u8 bit value > @@ -32,8 +31,7 @@ > */ > #define REG_BIT8(__n) \ > ((u8)(BIT(__n) + \ > - BUILD_BUG_ON_ZERO(__is_constexpr(__n) && \ > - ((__n) < 0 || (__n) > 7)))) > + BUILD_BUG_ON_ZERO(is_const_true((__n) < 0 || (__n) > 7)))) > > /** > * REG_GENMASK() - Prepare a continuous u32 bitmask > @@ -46,9 +44,9 @@ > */ > #define REG_GENMASK(__high, __low) \ > ((u32)(GENMASK(__high, __low) + \ > - BUILD_BUG_ON_ZERO(__is_constexpr(__high) && \ > - __is_constexpr(__low) && \ > - ((__low) < 0 || (__high) > 31 || (__low) > (__high))))) > + BUILD_BUG_ON_ZERO(is_const_true((__low) < 0 || \ > + (__high) > 31 || \ > + (__low) > (__high))))) > > /** > * REG_GENMASK64() - Prepare a continuous u64 bitmask > @@ -61,9 +59,9 @@ > */ > #define REG_GENMASK64(__high, __low) \ > ((u64)(GENMASK_ULL(__high, __low) + \ > - BUILD_BUG_ON_ZERO(__is_constexpr(__high) && \ > - __is_constexpr(__low) && \ > - ((__low) < 0 || (__high) > 63 || (__low) > (__high))))) > + BUILD_BUG_ON_ZERO(is_const_true((__low) < 0 || \ > + (__high) > 63 || \ > + (__low) > (__high))))) > > /** > * REG_GENMASK8() - Prepare a continuous u8 bitmask > @@ -76,9 +74,9 @@ > */ > #define REG_GENMASK8(__high, __low) \ > ((u8)(GENMASK(__high, __low) + \ > - BUILD_BUG_ON_ZERO(__is_constexpr(__high) && \ > - __is_constexpr(__low) && \ > - ((__low) < 0 || (__high) > 7 || (__low) > (__high))))) > + BUILD_BUG_ON_ZERO(is_const_true((__low) < 0 || \ > + (__high) > 7 || \ > + (__low) > (__high))))) > > /* > * Local integer constant expression version of is_power_of_2(). > @@ -97,10 +95,10 @@ > */ > #define REG_FIELD_PREP(__mask, __val) \ > ((u32)((((typeof(__mask))(__val) << __bf_shf(__mask)) & (__mask)) + \ > - BUILD_BUG_ON_ZERO(!__is_constexpr(__mask)) + \ > + BUILD_BUG_ON_ZERO(!is_const(__mask)) + \ > BUILD_BUG_ON_ZERO((__mask) == 0 || (__mask) > U32_MAX) + \ > BUILD_BUG_ON_ZERO(!IS_POWER_OF_2((__mask) + (1ULL << __bf_shf(__mask)))) + \ > - BUILD_BUG_ON_ZERO(__builtin_choose_expr(__is_constexpr(__val), (~((__mask) >> > __bf_shf(__mask)) & (__val)), 0)))) > + BUILD_BUG_ON_ZERO(is_const_true(~((__mask) >> __bf_shf(__mask)) & (__val))))) > > /** > * REG_FIELD_PREP8() - Prepare a u8 bitfield value > @@ -114,10 +112,10 @@ > */ > #define REG_FIELD_PREP8(__mask, __val) \ > ((u8)((((typeof(__mask))(__val) << __bf_shf(__mask)) & (__mask)) + \ > - BUILD_BUG_ON_ZERO(!__is_constexpr(__mask)) + \ > + BUILD_BUG_ON_ZERO(!is_const(__mask)) + \ > BUILD_BUG_ON_ZERO((__mask) == 0 || (__mask) > U8_MAX) + \ > BUILD_BUG_ON_ZERO(!IS_POWER_OF_2((__mask) + (1ULL << __bf_shf(__mask)))) + \ > - BUILD_BUG_ON_ZERO(__builtin_choose_expr(__is_constexpr(__val), (~((__mask) >> > __bf_shf(__mask)) & (__val)), 0)))) > + BUILD_BUG_ON_ZERO(is_const_true(~((__mask) >> __bf_shf(__mask)) & (__val))))) > > /** > * REG_FIELD_GET() - Extract a u32 bitfield value > @@ -154,8 +152,7 @@ > */ > #define REG_BIT16(__n) \ > ((u16)(BIT(__n) + \ > - BUILD_BUG_ON_ZERO(__is_constexpr(__n) && \ > - ((__n) < 0 || (__n) > 15)))) > + BUILD_BUG_ON_ZERO(is_const_true((__n) < 0 || (__n) > 15)))) > > /** > * REG_GENMASK16() - Prepare a continuous u8 bitmask > @@ -169,9 +166,9 @@ > */ > #define REG_GENMASK16(__high, __low) \ > ((u16)(GENMASK(__high, __low) + \ > - BUILD_BUG_ON_ZERO(__is_constexpr(__high) && \ > - __is_constexpr(__low) && \ > - ((__low) < 0 || (__high) > 15 || (__low) > (__high))))) > + BUILD_BUG_ON_ZERO(is_const_true((__low) < 0 || \ > + (__high) > 15 || \ > + (__low) > (__high))))) > > /** > * REG_FIELD_PREP16() - Prepare a u16 bitfield value > @@ -186,10 +183,10 @@ > */ > #define REG_FIELD_PREP16(__mask, __val) \ > ((u16)((((typeof(__mask))(__val) << __bf_shf(__mask)) & (__mask)) + \ > - BUILD_BUG_ON_ZERO(!__is_constexpr(__mask)) + \ > + BUILD_BUG_ON_ZERO(!is_const(__mask)) + \ > BUILD_BUG_ON_ZERO((__mask) == 0 || (__mask) > U16_MAX) + \ > BUILD_BUG_ON_ZERO(!IS_POWER_OF_2((__mask) + (1ULL << __bf_shf(__mask)))) + \ > - BUILD_BUG_ON_ZERO(__builtin_choose_expr(__is_constexpr(__val), (~((__mask) >> > __bf_shf(__mask)) & (__val)), 0)))) > + BUILD_BUG_ON_ZERO(is_const_true(~((__mask) >> __bf_shf(__mask)) & (__val))))) > > #define __MASKED_FIELD(mask, value) ((mask) << 16 | (value)) > #define _MASKED_FIELD(mask, value) ({ \ > @@ -237,7 +234,7 @@ > * ... > */ > #define _PICK_EVEN_2RANGES(__index, __c_index, __a, __b, __c, __d) \ > - (BUILD_BUG_ON_ZERO(!__is_constexpr(__c_index)) + \ > + (BUILD_BUG_ON_ZERO(!is_const(__c_index)) + \ > ((__index) < (__c_index) ? _PICK_EVEN(__index, __a, __b) : \ > _PICK_EVEN((__index) - (__c_index), __c, __d))) > > > -- > 2.45.2 > > - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
On Thu. 5 Dec 2024 at 04:00, David Laight <David.Laight@aculab.com> wrote: > From: Vincent Mailhol > > Sent: 02 December 2024 17:34 > > > > Most of the use of __is_const_expr() in i915_reg_defs.h are just to > > test whether an expression is known to be true. Because those checks > > are all done in a BUILD_BUG_ON_ZERO(), replace those with > > is_const_true(). > > Another place that could use statically_true() and BUILD_BUG_ON_MSG(). Here also, BUILD_BUG_ON_MSG() is not suitable because it does not return a value. __BUILD_BUG_ON_ZERO_MSG() could be used; but there is less benefit to do this at a driver scope. In this i915_reg_defs.h, BUILD_BUG_ON_ZERO() is used 20 times. Adding an error message each time will just make things ugly. If we want more readable error messages here, the solution for me is just to redefine BUILD_BUG_ON_ZERO() to print a more meaningful error message by default. But this is not the scope of this series. I sent a separate patch for this: https://lore.kernel.org/all/20241205151316.1480255-2-mailhol.vincent@wanadoo.fr/ Concerning statically_true() instead of is_const_true(), let me test, and if this works, then I will replace these in v2. Yours sincerely, Vincent Mailhol
diff --git a/drivers/gpu/drm/i915/i915_reg_defs.h b/drivers/gpu/drm/i915/i915_reg_defs.h index e251bcc0c89f5710125bc70f07851b2cb978c89c..6ed2fb9cf506a3bd6467ba30f9d0e863d62762f3 100644 --- a/drivers/gpu/drm/i915/i915_reg_defs.h +++ b/drivers/gpu/drm/i915/i915_reg_defs.h @@ -19,8 +19,7 @@ */ #define REG_BIT(__n) \ ((u32)(BIT(__n) + \ - BUILD_BUG_ON_ZERO(__is_constexpr(__n) && \ - ((__n) < 0 || (__n) > 31)))) + BUILD_BUG_ON_ZERO(is_const_true((__n) < 0 || (__n) > 31)))) /** * REG_BIT8() - Prepare a u8 bit value @@ -32,8 +31,7 @@ */ #define REG_BIT8(__n) \ ((u8)(BIT(__n) + \ - BUILD_BUG_ON_ZERO(__is_constexpr(__n) && \ - ((__n) < 0 || (__n) > 7)))) + BUILD_BUG_ON_ZERO(is_const_true((__n) < 0 || (__n) > 7)))) /** * REG_GENMASK() - Prepare a continuous u32 bitmask @@ -46,9 +44,9 @@ */ #define REG_GENMASK(__high, __low) \ ((u32)(GENMASK(__high, __low) + \ - BUILD_BUG_ON_ZERO(__is_constexpr(__high) && \ - __is_constexpr(__low) && \ - ((__low) < 0 || (__high) > 31 || (__low) > (__high))))) + BUILD_BUG_ON_ZERO(is_const_true((__low) < 0 || \ + (__high) > 31 || \ + (__low) > (__high))))) /** * REG_GENMASK64() - Prepare a continuous u64 bitmask @@ -61,9 +59,9 @@ */ #define REG_GENMASK64(__high, __low) \ ((u64)(GENMASK_ULL(__high, __low) + \ - BUILD_BUG_ON_ZERO(__is_constexpr(__high) && \ - __is_constexpr(__low) && \ - ((__low) < 0 || (__high) > 63 || (__low) > (__high))))) + BUILD_BUG_ON_ZERO(is_const_true((__low) < 0 || \ + (__high) > 63 || \ + (__low) > (__high))))) /** * REG_GENMASK8() - Prepare a continuous u8 bitmask @@ -76,9 +74,9 @@ */ #define REG_GENMASK8(__high, __low) \ ((u8)(GENMASK(__high, __low) + \ - BUILD_BUG_ON_ZERO(__is_constexpr(__high) && \ - __is_constexpr(__low) && \ - ((__low) < 0 || (__high) > 7 || (__low) > (__high))))) + BUILD_BUG_ON_ZERO(is_const_true((__low) < 0 || \ + (__high) > 7 || \ + (__low) > (__high))))) /* * Local integer constant expression version of is_power_of_2(). @@ -97,10 +95,10 @@ */ #define REG_FIELD_PREP(__mask, __val) \ ((u32)((((typeof(__mask))(__val) << __bf_shf(__mask)) & (__mask)) + \ - BUILD_BUG_ON_ZERO(!__is_constexpr(__mask)) + \ + BUILD_BUG_ON_ZERO(!is_const(__mask)) + \ BUILD_BUG_ON_ZERO((__mask) == 0 || (__mask) > U32_MAX) + \ BUILD_BUG_ON_ZERO(!IS_POWER_OF_2((__mask) + (1ULL << __bf_shf(__mask)))) + \ - BUILD_BUG_ON_ZERO(__builtin_choose_expr(__is_constexpr(__val), (~((__mask) >> __bf_shf(__mask)) & (__val)), 0)))) + BUILD_BUG_ON_ZERO(is_const_true(~((__mask) >> __bf_shf(__mask)) & (__val))))) /** * REG_FIELD_PREP8() - Prepare a u8 bitfield value @@ -114,10 +112,10 @@ */ #define REG_FIELD_PREP8(__mask, __val) \ ((u8)((((typeof(__mask))(__val) << __bf_shf(__mask)) & (__mask)) + \ - BUILD_BUG_ON_ZERO(!__is_constexpr(__mask)) + \ + BUILD_BUG_ON_ZERO(!is_const(__mask)) + \ BUILD_BUG_ON_ZERO((__mask) == 0 || (__mask) > U8_MAX) + \ BUILD_BUG_ON_ZERO(!IS_POWER_OF_2((__mask) + (1ULL << __bf_shf(__mask)))) + \ - BUILD_BUG_ON_ZERO(__builtin_choose_expr(__is_constexpr(__val), (~((__mask) >> __bf_shf(__mask)) & (__val)), 0)))) + BUILD_BUG_ON_ZERO(is_const_true(~((__mask) >> __bf_shf(__mask)) & (__val))))) /** * REG_FIELD_GET() - Extract a u32 bitfield value @@ -154,8 +152,7 @@ */ #define REG_BIT16(__n) \ ((u16)(BIT(__n) + \ - BUILD_BUG_ON_ZERO(__is_constexpr(__n) && \ - ((__n) < 0 || (__n) > 15)))) + BUILD_BUG_ON_ZERO(is_const_true((__n) < 0 || (__n) > 15)))) /** * REG_GENMASK16() - Prepare a continuous u8 bitmask @@ -169,9 +166,9 @@ */ #define REG_GENMASK16(__high, __low) \ ((u16)(GENMASK(__high, __low) + \ - BUILD_BUG_ON_ZERO(__is_constexpr(__high) && \ - __is_constexpr(__low) && \ - ((__low) < 0 || (__high) > 15 || (__low) > (__high))))) + BUILD_BUG_ON_ZERO(is_const_true((__low) < 0 || \ + (__high) > 15 || \ + (__low) > (__high))))) /** * REG_FIELD_PREP16() - Prepare a u16 bitfield value @@ -186,10 +183,10 @@ */ #define REG_FIELD_PREP16(__mask, __val) \ ((u16)((((typeof(__mask))(__val) << __bf_shf(__mask)) & (__mask)) + \ - BUILD_BUG_ON_ZERO(!__is_constexpr(__mask)) + \ + BUILD_BUG_ON_ZERO(!is_const(__mask)) + \ BUILD_BUG_ON_ZERO((__mask) == 0 || (__mask) > U16_MAX) + \ BUILD_BUG_ON_ZERO(!IS_POWER_OF_2((__mask) + (1ULL << __bf_shf(__mask)))) + \ - BUILD_BUG_ON_ZERO(__builtin_choose_expr(__is_constexpr(__val), (~((__mask) >> __bf_shf(__mask)) & (__val)), 0)))) + BUILD_BUG_ON_ZERO(is_const_true(~((__mask) >> __bf_shf(__mask)) & (__val))))) #define __MASKED_FIELD(mask, value) ((mask) << 16 | (value)) #define _MASKED_FIELD(mask, value) ({ \ @@ -237,7 +234,7 @@ * ... */ #define _PICK_EVEN_2RANGES(__index, __c_index, __a, __b, __c, __d) \ - (BUILD_BUG_ON_ZERO(!__is_constexpr(__c_index)) + \ + (BUILD_BUG_ON_ZERO(!is_const(__c_index)) + \ ((__index) < (__c_index) ? _PICK_EVEN(__index, __a, __b) : \ _PICK_EVEN((__index) - (__c_index), __c, __d)))