This series is the spiritual successor of [1] which introduced
const_true(). In [1], following a comment from David Laight, Linus
came with a suggestion to simplify __is_constexpr() and its derived
macros using a _Generic() selection. Because of the total change of
scope, I am starting a new series.
The goal is to introduce a set of three macros:
- is_const(): a one to one replacement of __is_constexpr() in term
of features but written in a less hacky way thanks to _Generic().
- is_const_true(): tells whether or not the argument is a true
integer constant expression.
- is_const_false(): tells whether or not the argument is a false
integer constant expression.
Once defined, apply them tree-wide.
All those three macros will rely on a single building block:
__is_const_zero().
Patch 1 adds statically_false(). This is just done so that at the end
of this series, the full set of statically_true/false() and
is_const_true/false() is present.
Patch 2 adds __is_const_zero() and is_const().
Patch 3 adds is_const_true() and is_const_false().
Patch 4 to 9 do a tree-wide replacement to remove all the usages of
__is_constexpr() and replace them by is_const_true() or
is_const_false() whenever feasible, or by is_const() otherwise.
Patch 10 finally remove __is_constexpr(). RIP!
[1] add const_true() to simplify GENMASK_INPUT_CHECK()
Link: https://lore.kernel.org/all/20241113172939.747686-4-mailhol.vincent@xxxxxxxxxx/
Signed-off-by: Vincent Mailhol <mailhol.vincent@xxxxxxxxxx>
---
Vincent Mailhol (10):
compiler.h: add statically_false()
compiler.h: add is_const() as a replacement of __is_constexpr()
compiler.h: add is_const_true() and is_const_false()
linux/bits.h: simplify GENMASK_INPUT_CHECK() by using is_const_true()
minmax: simplify __clamp_once() by using is_const_false()
fortify: replace __is_constexpr() by is_const() in strlen()
overflow: replace __is_constexpr() by is_const()
drm/i915/reg: replace __is_const_expr() by is_const_true() or is_const()
coresight: etm4x: replace __is_const_expr() by is_const()
compiler.h: remove __is_constexpr()
drivers/gpu/drm/i915/i915_reg_defs.h | 47 +++++------
drivers/hwtracing/coresight/coresight-etm4x.h | 2 +-
include/linux/bits.h | 5 +-
include/linux/compiler.h | 112 +++++++++++++++-----------
include/linux/fortify-string.h | 4 +-
include/linux/minmax.h | 3 +-
include/linux/overflow.h | 8 +-
7 files changed, 97 insertions(+), 84 deletions(-)
---
base-commit: e70140ba0d2b1a30467d4af6bcfe761327b9ec95
change-id: 20241129-is_constexpr-refactor-19460adedc48
Best regards,
--
Vincent Mailhol <mailhol.vincent@xxxxxxxxxx>
