The compiler can figure this out

cataphract · cataphract · commit e5029ac40bd8 · 2013-01-14T12:22:42.000+01:00
diff --git a/ext/standard/string.c b/ext/standard/string.c
@@ -2821,7 +2821,7 @@ static inline HASH php_strtr_hash(const char *str, int len)
 	HASH	res = 0;
 	int		i;
 	for (i = 0; i < len; i++) {
-		res = (res << 5) + res + (unsigned char)str[i];
+		res = res * 33 + (unsigned char)str[i];
 	}
 
 	return res;

Original file line number	Diff line number	Diff line change
`@@ -2821,7 +2821,7 @@ static inline HASH php_strtr_hash(const char *str, int len)`
`2821`	`2821`	`HASH res = 0;`
`2822`	`2822`	`int i;`
`2823`	`2823`	`for (i = 0; i < len; i++) {`
`2824`		`- res = (res << 5) + res + (unsigned char)str[i];`
	`2824`	`+ res = res * 33 + (unsigned char)str[i];`
`2825`	`2825`	`}`
`2826`	`2826`
`2827`	`2827`	`return res;`