Re: [PATCH] hwmon: (minisforum-um780xtx) Fix clamp() build failure with GCC 11
From: Paul E. McKenney
Date: Mon Oct 19 2026 - 14:55:53 EST
On Sun, Oct 18, 2026 at 09:16:44AM -0700, Guenter Roeck wrote:
> On Wed, Oct 14, 2026 at 06:45:22PM -0300, Sebastián Peyrott wrote:
> > GCC 11 fails to build the driver:
> >
> > error: call to '__compiletime_assert_727' declared with attribute error:
> > clamp() low limit 0 greater than high limit points[1] - 1
> >
> > The store function returns -EIO unless points[0] < points[1], so
> > points[1] - 1 cannot be negative when the clamp is reached. GCC 11 jump
> > threading, however, duplicates the clamp() limit check and does not prune
> > the copy in which points[1] is zero, so the compile-time check in clamp()
> > fires on an unreachable path. GCC 8 to 10 and 12 to 16 accept the code.
> >
> > Select both limits first and use a single clamp_val(). This does not
> > change behavior.
> >
> > Fixes: 9d980da93bbc ("hwmon: Add Minisforum UM780 XTX EC monitoring and fan control")
> > Reported-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> > Closes: https://lore.kernel.org/r/fda0e59f-20e1-4a94-a714-288940dcdd37@paulmck-laptop
> > Assisted-by: LLM
> > Signed-off-by: Sebastián Peyrott <speyrott@xxxxxxxxx>
> > Tested-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
>
> Folded into original patch, as suggested.
Thank you both!
Thanx, Paul