| Message ID | 20171114172653.6690-1-colin.king@canonical.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, 14 Nov 2017 18:26:53 +0100, Colin King wrote: > > From: Colin Ian King <colin.king@canonical.com> > > The calculation r = (3 - ((rate >> 6) & 3)) * 3 results in r being > 0, 3, 6 or 9 and so the check (13 > r) is always true and hence we > can remove the redundant check and the else path. > > Detected by CoverityScan, CID#744415 ("Logically dead code") > > Signed-off-by: Colin Ian King <colin.king@canonical.com> The calculation of t itself can be generic in case we may add a support greater than the current r, so I don't think it's so much beneficial with this code reduction. Better to keep the code as reference. thanks, Takashi > --- > sound/synth/emux/soundfont.c | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > > diff --git a/sound/synth/emux/soundfont.c b/sound/synth/emux/soundfont.c > index 31a4ea94830e..0beb5a737c8b 100644 > --- a/sound/synth/emux/soundfont.c > +++ b/sound/synth/emux/soundfont.c > @@ -858,10 +858,7 @@ calc_gus_envelope_time(int rate, int start, int end) > p = rate & 0x3f; > t = end - start; > if (t < 0) t = -t; > - if (13 > r) > - t = t << (13 - r); > - else > - t = t >> (r - 13); > + t = t << (13 - r); > return (t * 10) / (p * 441); > } > > -- > 2.14.1 > >
On 17/11/17 11:06, Takashi Iwai wrote: > On Tue, 14 Nov 2017 18:26:53 +0100, > Colin King wrote: >> >> From: Colin Ian King <colin.king@canonical.com> >> >> The calculation r = (3 - ((rate >> 6) & 3)) * 3 results in r being >> 0, 3, 6 or 9 and so the check (13 > r) is always true and hence we >> can remove the redundant check and the else path. >> >> Detected by CoverityScan, CID#744415 ("Logically dead code") >> >> Signed-off-by: Colin Ian King <colin.king@canonical.com> > > The calculation of t itself can be generic in case we may add a > support greater than the current r, so I don't think it's so much > beneficial with this code reduction. Better to keep the code as > reference. OK, that's a good decision. Colin > > > thanks, > > Takashi > >> --- >> sound/synth/emux/soundfont.c | 5 +---- >> 1 file changed, 1 insertion(+), 4 deletions(-) >> >> diff --git a/sound/synth/emux/soundfont.c b/sound/synth/emux/soundfont.c >> index 31a4ea94830e..0beb5a737c8b 100644 >> --- a/sound/synth/emux/soundfont.c >> +++ b/sound/synth/emux/soundfont.c >> @@ -858,10 +858,7 @@ calc_gus_envelope_time(int rate, int start, int end) >> p = rate & 0x3f; >> t = end - start; >> if (t < 0) t = -t; >> - if (13 > r) >> - t = t << (13 - r); >> - else >> - t = t >> (r - 13); >> + t = t << (13 - r); >> return (t * 10) / (p * 441); >> } >> >> -- >> 2.14.1 >> >> > -- > To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
Am 17.11.2017 12:07, schrieb Colin Ian King: > On 17/11/17 11:06, Takashi Iwai wrote: >> On Tue, 14 Nov 2017 18:26:53 +0100, >> Colin King wrote: >>> >>> From: Colin Ian King <colin.king@canonical.com> >>> >>> The calculation r = (3 - ((rate >> 6) & 3)) * 3 results in r being >>> 0, 3, 6 or 9 and so the check (13 > r) is always true and hence we >>> can remove the redundant check and the else path. >>> >>> Detected by CoverityScan, CID#744415 ("Logically dead code") >>> >>> Signed-off-by: Colin Ian King <colin.king@canonical.com> >> >> The calculation of t itself can be generic in case we may add a >> support greater than the current r, so I don't think it's so much >> beneficial with this code reduction. Better to keep the code as >> reference. > > OK, that's a good decision. > NTL is should be documented that this is intentional before the next scanner finds it. just my 2 cents, re, wh > Colin >> >> >> thanks, >> >> Takashi >> >>> --- >>> sound/synth/emux/soundfont.c | 5 +---- >>> 1 file changed, 1 insertion(+), 4 deletions(-) >>> >>> diff --git a/sound/synth/emux/soundfont.c b/sound/synth/emux/soundfont.c >>> index 31a4ea94830e..0beb5a737c8b 100644 >>> --- a/sound/synth/emux/soundfont.c >>> +++ b/sound/synth/emux/soundfont.c >>> @@ -858,10 +858,7 @@ calc_gus_envelope_time(int rate, int start, int end) >>> p = rate & 0x3f; >>> t = end - start; >>> if (t < 0) t = -t; >>> - if (13 > r) >>> - t = t << (13 - r); >>> - else >>> - t = t >> (r - 13); >>> + t = t << (13 - r); >>> return (t * 10) / (p * 441); >>> } >>> >>> -- >>> 2.14.1 >>> >>> >> -- >> To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > -- > To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html >
diff --git a/sound/synth/emux/soundfont.c b/sound/synth/emux/soundfont.c index 31a4ea94830e..0beb5a737c8b 100644 --- a/sound/synth/emux/soundfont.c +++ b/sound/synth/emux/soundfont.c @@ -858,10 +858,7 @@ calc_gus_envelope_time(int rate, int start, int end) p = rate & 0x3f; t = end - start; if (t < 0) t = -t; - if (13 > r) - t = t << (13 - r); - else - t = t >> (r - 13); + t = t << (13 - r); return (t * 10) / (p * 441); }