diff options
author | Thomas Rast <trast@student.ethz.ch> | 2012-05-01 14:23:20 +0400 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2012-05-01 23:19:06 +0400 |
commit | 6f1af028ce0654ef6233dff06701a989d5703bc4 (patch) | |
tree | 0ca643139204f751c4231d3800ba3fbde61f62ab /xdiff/xutils.c | |
parent | 6942efcfa9f3083e7c7863348fa5bb1350412595 (diff) |
xdiff: choose XDL_FAST_HASH code on sizeof(long) instead of __WORDSIZE
Darwin does not define __WORDSIZE, and compiles the 32-bit code path
on 64-bit systems, resulting in a totally broken git.
I could not find an alternative -- other than the platform symbols
(__x86_64__ etc.) -- that does the test in the preprocessor. However,
we can also just test for the size of a 'long', which is what really
matters here. Any compiler worth its salt will leave only the branch
relevant for its platform, and indeed on Linux/GCC the numbers don't
change:
Test tr/darwin-xdl-fast-hash origin/next origin/master
------------------------------------------------------------------------------------------------------------------
4000.1: log -3000 (baseline) 0.09(0.07+0.01) 0.09(0.07+0.01) -5.5%* 0.09(0.07+0.01) -4.1%
4000.2: log --raw -3000 (tree-only) 0.47(0.41+0.05) 0.47(0.40+0.05) -0.5% 0.45(0.38+0.06) -3.5%.
4000.3: log -p -3000 (Myers) 1.81(1.67+0.12) 1.81(1.67+0.13) +0.3% 1.99(1.84+0.12) +10.2%***
4000.4: log -p -3000 --histogram 1.79(1.66+0.11) 1.80(1.67+0.11) +0.4% 1.96(1.82+0.10) +9.2%***
4000.5: log -p -3000 --patience 2.17(2.02+0.13) 2.20(2.04+0.13) +1.3%. 2.33(2.18+0.13) +7.4%***
------------------------------------------------------------------------------------------------------------------
Significance hints: '.' 0.1 '*' 0.05 '**' 0.01 '***' 0.001
Noticed-by: Brian Gernhardt <brian@gernhardtsoftware.com>
Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'xdiff/xutils.c')
-rw-r--r-- | xdiff/xutils.c | 52 |
1 files changed, 23 insertions, 29 deletions
diff --git a/xdiff/xutils.c b/xdiff/xutils.c index e05b5c96aa..1b3b471ac8 100644 --- a/xdiff/xutils.c +++ b/xdiff/xutils.c @@ -290,39 +290,33 @@ static inline unsigned long has_zero(unsigned long a) return ((a - ONEBYTES) & ~a) & HIGHBITS; } -#if __WORDSIZE == 64 - -/* - * Jan Achrenius on G+: microoptimized version of - * the simpler "(mask & ONEBYTES) * ONEBYTES >> 56" - * that works for the bytemasks without having to - * mask them first. - */ static inline long count_masked_bytes(unsigned long mask) { - return mask * 0x0001020304050608 >> 56; -} - -#else /* 32-bit case */ - -/* Modified Carl Chatfield G+ version for 32-bit */ -static inline long count_masked_bytes(long mask) -{ - /* - * (a) gives us - * -1 (0, ff), 0 (ffff) or 1 (ffffff) - * (b) gives us - * 0 for 0, 1 for (ff ffff ffffff) - * (a+b+1) gives us - * correct 0-3 bytemask count result - */ - long a = (mask - 256) >> 23; - long b = mask & 1; - return a + b + 1; + if (sizeof(long) == 8) { + /* + * Jan Achrenius on G+: microoptimized version of + * the simpler "(mask & ONEBYTES) * ONEBYTES >> 56" + * that works for the bytemasks without having to + * mask them first. + */ + return mask * 0x0001020304050608 >> 56; + } else { + /* + * Modified Carl Chatfield G+ version for 32-bit * + * + * (a) gives us + * -1 (0, ff), 0 (ffff) or 1 (ffffff) + * (b) gives us + * 0 for 0, 1 for (ff ffff ffffff) + * (a+b+1) gives us + * correct 0-3 bytemask count result + */ + long a = (mask - 256) >> 23; + long b = mask & 1; + return a + b + 1; + } } -#endif - unsigned long xdl_hash_record(char const **data, char const *top, long flags) { unsigned long hash = 5381; |