Hi, On 29-Sep-24 11:34 PM, David Laight wrote: > From: Ricardo Ribalda >> Sent: 27 September 2024 10:42 >> >> The max() macro produce nicer code and also fixes the following cocci >> errors: >> >> drivers/staging/media/atomisp/pci/sh_css_frac.h:40:17-18: WARNING opportunity for max() >> drivers/staging/media/atomisp/pci/sh_css_frac.h:50:17-18: WARNING opportunity for max() >> >> Signed-off-by: Ricardo Ribalda <ribalda@xxxxxxxxxxxx> >> --- >> drivers/staging/media/atomisp/pci/sh_css_frac.h | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/staging/media/atomisp/pci/sh_css_frac.h >> b/drivers/staging/media/atomisp/pci/sh_css_frac.h >> index 8ba65161f7a9..9642506d2388 100644 >> --- a/drivers/staging/media/atomisp/pci/sh_css_frac.h >> +++ b/drivers/staging/media/atomisp/pci/sh_css_frac.h >> @@ -37,7 +37,7 @@ static inline int sDIGIT_FITTING(int v, int a, int b) >> int fit_shift = sFRACTION_BITS_FITTING(a) - b; >> >> v >>= sSHIFT; > > IIRC right shifts of signed values are undefined. > (C does not require a cpu to have a right shift that replicates the > sign bit.) > >> - v >>= fit_shift > 0 ? fit_shift : 0; >> + v >>= max(fit_shift, 0); > > If the shift isn't done the return value is garbage. > So the code better not let it happen. > In which case you might as well let the cpu generate a (different) > random value - so delete the conditional. Given the history of this code I would no be surprised if some weird corner case actually relies on the check, so NACK for dropping the conditional. > >> >> return clamp_t(int, v, sISP_VAL_MIN, sISP_VAL_MAX); > > all three values seem to be 'int' - so no need for the _t variant > and all the associated casts. sDIGIT_FITTING() originally was a macro with a bunch of max() + min() calls nested leading to it expanding to a lot of code after running it through the pre-processor. When converting this to a static online to choice was made to with clamp_t() to avoid the overhead of the extra type checks in regular clamp(). Regards, Hans > >> } >> @@ -47,7 +47,7 @@ static inline unsigned int uDIGIT_FITTING(unsigned int v, int a, int b) >> int fit_shift = uFRACTION_BITS_FITTING(a) - b; >> >> v >>= uSHIFT; >> - v >>= fit_shift > 0 ? fit_shift : 0; >> + v >>= max(fit_shift, 0); >> >> return clamp_t(unsigned int, v, uISP_VAL_MIN, uISP_VAL_MAX); > > as above, but it is just min(v, iISP_VAL_MAX) > > David > >> } >> >> -- >> 2.46.1.824.gd892dcdcdd-goog >> > > - > Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK > Registration No: 1397386 (Wales)
