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authorStefan Beller <stefanbeller@googlemail.com>2013-08-16 21:22:37 (GMT)
committerJunio C Hamano <gitster@pobox.com>2013-08-18 19:56:23 (GMT)
commitf7466e94375b3be27f229c78873f0acf8301c0a5 (patch)
treee89ea9893dc333d60231d0447b7b67973a3dff21 /diff-delta.c
parentedca4152560522a431a51fc0a06147fc680b5b18 (diff)
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create_delta_index: simplify condition always evaluating to true
The code sequence ' (1u << i) < hsize && i < 31 ' is a multi step process, whose first step requires that 'i' is already less that 31, otherwise the result (1u << i) is undefined (and 'undef_val < hsize' can therefore be assumed to be 'false'), and so the later test i < 31 can always be optimized away as dead code ('i' is already less than 31, or the short circuit 'and' applies). So we need to get rid of that code. One way would be to exchange the order of the conditions, so the expression 'i < 31 && (1u << i) < hsize' would remove that optimized unstable code already. However when checking the previous lines in that function, we can deduce that 'hsize' must always be smaller than (1u<<31), since 506049c7df2c6 (fix >4GiB source delta assertion failure), because 'entries' is capped at an upper bound of 0xfffffffeU, so 'hsize' contains a maximum value of 0x3fffffff, which is smaller than (1u<<31), so the value of 'i' will never be larger than 31 and we can remove that condition entirely. Signed-off-by: Stefan Beller <stefanbeller@googlemail.com> Acked-by: Nicolas Pitre <nico@fluxnic.net> Acked-by: Philip Oakley <philipoakley@iee.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'diff-delta.c')
-rw-r--r--diff-delta.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/diff-delta.c b/diff-delta.c
index 93385e1..3797ce6 100644
--- a/diff-delta.c
+++ b/diff-delta.c
@@ -155,7 +155,7 @@ struct delta_index * create_delta_index(const void *buf, unsigned long bufsize)
entries = 0xfffffffeU / RABIN_WINDOW;
}
hsize = entries / 4;
- for (i = 4; (1u << i) < hsize && i < 31; i++);
+ for (i = 4; (1u << i) < hsize; i++);
hsize = 1 << i;
hmask = hsize - 1;