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| author | Denys Vlasenko <vda.linux@googlemail.com> | 2010-01-18 05:22:34 +0100 |
|---|---|---|
| committer | Denys Vlasenko <vda.linux@googlemail.com> | 2010-01-18 05:22:34 +0100 |
| commit | 032bf6553346537cb02d0406c05548c8aa23c81f (patch) | |
| tree | 231b695138da8661547e331c3b43c7ee438c5194 | |
| parent | d4a7728dc3b37e2956034f18fc26c04bc0aa2b0e (diff) | |
| download | busybox-032bf6553346537cb02d0406c05548c8aa23c81f.tar.gz | |
diff: defeat gcc's optimization
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
| -rw-r--r-- | editors/diff.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/editors/diff.c b/editors/diff.c index af6917a03..b89bbc1dc 100644 --- a/editors/diff.c +++ b/editors/diff.c @@ -435,7 +435,10 @@ static int *create_J(FILE_and_pos_t ft[2], int nlen[2], off_t *ix[2]) tok = read_token(&ft[i], tok); if (!(tok & TOK_EMPTY)) { /* Hash algorithm taken from Robert Sedgewick, Algorithms in C, 3d ed., p 578. */ - hash = hash * 128 - hash + TOK2CHAR(tok); + /*hash = hash * 128 - hash + TOK2CHAR(tok); + * gcc insists on optimizing above to "hash * 127 + ...", thus... */ + unsigned o = hash - TOK2CHAR(tok); + hash = hash * 128 - o; /* we want SPEED here */ continue; } if (nlen[i]++ == sz) { |