[alsa-devel] [PATCH] ALSA: synth: emux: remove redundant test for r <= 13
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 --- 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); }
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
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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
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participants (4)
-
Colin Ian King -
Colin King
-
Takashi Iwai -
walter harms