On Tue, Jul 14, 2020 at 4:51 PM Lee Jones <lee.jo...@linaro.org> wrote: > > If we fail to use a variable, even a 'dummy' one, then the compiler > complains that it is set but not used. We know this is fine, so we > set it to its own value here.
Which is kind of ugly in my personal view. I hope that the compiler will actually optimize the extra code away ... > Fixes the following W=1 kernel build warning(s): Well, "Makes the following ... warning(s) go away:" rather ... > drivers/cpufreq/acpi-cpufreq.c: In function ‘cpu_freq_read_intel’: > drivers/cpufreq/acpi-cpufreq.c:247:11: warning: variable ‘dummy’ set but not > used [-Wunused-but-set-variable] > drivers/cpufreq/acpi-cpufreq.c: In function ‘cpu_freq_read_amd’: > drivers/cpufreq/acpi-cpufreq.c:265:11: warning: variable ‘dummy’ set but not > used [-Wunused-but-set-variable] > > Cc: Andy Grover <andrew.gro...@intel.com> > Cc: Paul Diefenbaugh <paul.s.diefenba...@intel.com> > Cc: Dominik Brodowski <li...@brodo.de> > Cc: Denis Sadykov <denis.m.sady...@intel.com> > Signed-off-by: Lee Jones <lee.jo...@linaro.org> > --- > drivers/cpufreq/acpi-cpufreq.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/cpufreq/acpi-cpufreq.c b/drivers/cpufreq/acpi-cpufreq.c > index 429e5a36c08a9..d38a693b48e03 100644 > --- a/drivers/cpufreq/acpi-cpufreq.c > +++ b/drivers/cpufreq/acpi-cpufreq.c > @@ -247,6 +247,7 @@ static u32 cpu_freq_read_intel(struct acpi_pct_register > *not_used) > u32 val, dummy; > > rdmsr(MSR_IA32_PERF_CTL, val, dummy); > + dummy &= dummy; /* Silence set but not used warning */ > return val; > } > > @@ -264,6 +265,7 @@ static u32 cpu_freq_read_amd(struct acpi_pct_register > *not_used) > u32 val, dummy; > > rdmsr(MSR_AMD_PERF_CTL, val, dummy); > + dummy &= dummy; /* Silence set but not used warning */ > return val; > } > > -- > 2.25.1 >
