[v2,0/8] minmax: reduce compilation time

Message

David Laight July 28, 2024, 2:15 p.m. UTC

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.

These changes reduce the expansions somewhat.
The biggest change is the last patch that directly implements
min3() and max3() rather than using a nested expansion.

Further significant improvements can be made by removing the
requirement that min(1,2) be 'constant enough' for an array size.
Instead supporing MIN() and MAX() for constants only with a result
that is valid for a static initialiser.
However that needs an initial change to the few files that have
local versions of MIN() or MAX().

Main changes for v2:
- Keep existing definition of __is_constexpr().
- Fix warning in signedness test for pointer types.
- Use __auto_type (From Arnd).

David Laight (8):
  minmax: Put all the clamp() definitions together
  minmax: Use _Static_assert() instead of static_assert()
  compiler.h: Add __if_constexpr(expr, if_const, if_not_const)
  minmax: Simplify signedness check
  minmax: Factor out the zero-extension logic from umin/umax.
  minmax: Optimise _Static_assert() check in clamp().
  minmax: Use __auto_type
  minmax: minmax: Add __types_ok3() and optimise defines with 3
    arguments

 include/linux/compiler.h |  17 ++++
 include/linux/minmax.h   | 188 +++++++++++++++++++++------------------
 2 files changed, 117 insertions(+), 88 deletions(-)