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| author | David 'Digit' Turner <digit@google.com> | 2010-09-28 00:15:05 -0700 |
|---|---|---|
| committer | Android (Google) Code Review <android-gerrit@google.com> | 2010-09-28 00:15:05 -0700 |
| commit | 79260746dbed91babab415ea86fba0e3eb086429 (patch) | |
| tree | d2d601aa76389e72fd8aca11e950cbe32742ac6d | |
| parent | 032a713549c12b79b5dde6ef3dff323b7698110d (diff) | |
| parent | 80fba9a2fe4eacaabee99cf0bbead872c2792231 (diff) | |
| download | bionic-79260746dbed91babab415ea86fba0e3eb086429.zip bionic-79260746dbed91babab415ea86fba0e3eb086429.tar.gz bionic-79260746dbed91babab415ea86fba0e3eb086429.tar.bz2 | |
Merge "libc: memmove(): non-overlapping block optim." into gingerbread
| -rw-r--r-- | libc/string/memmove.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/libc/string/memmove.c b/libc/string/memmove.c index fcaf4ee..948a766 100644 --- a/libc/string/memmove.c +++ b/libc/string/memmove.c @@ -31,7 +31,11 @@ void *memmove(void *dst, const void *src, size_t n) { const char *p = src; char *q = dst; - if (__builtin_expect(q < p, 1)) { + + /* we can use highgly-optimized memcpy() if the destination + * is before the source, or if the two blocks are non-overlapping + */ + if (__builtin_expect((q < p || (q-p) <= (ptrdiff_t)n), 1)) { return memcpy(dst, src, n); } else { #define PRELOAD_DISTANCE 64 |