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diff: defeat gcc's optimization

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Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2010-01-18 05:22:34 +01:00
parent d4a7728dc3
commit 032bf65533
1 changed files with 4 additions and 1 deletions
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editors/diff.c
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@ -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) {