Re: [PATCH 2/2] grep: don't call regexec() for fixed strings

> Add the new flag "fixed" to struct grep_pat and set it if the pattern
> is doesn't contain any regex control characters in addition to if the
> flag -F/--fixed-strings was specified.
>
> diff --git a/grep.c b/grep.c
> index 394703b..a1092df 100644
> --- a/grep.c
> +++ b/grep.c
> @@ -28,9 +28,31 @@ void append_grep_pattern(struct grep_opt *opt, const char *pat,
>        p->next = NULL;
>  }
>
> +static int isregexspecial(int c)
> +{
> +       return isspecial(c) || c == '$' || c == '(' || c == ')' || c == '+' ||
> +                              c == '.' || c == '^' || c == '{' || c == '|';
> +}