Re: [PATCH] Use ^=1 to toggle between 0 and 1
- From
- Dragan Simic <dsimic@manjaro.org>
- Date
- Dec 12, 2023, 17:29 UTC
- Message-ID
- <62c31371741b07ec5e012cb268294536@manjaro.org>
- In-Reply-To
- <pull.1620.git.git.1702401468082.gitgitgadget@gmail.com>
On 2023-12-12 18:17, AtariDreams via GitGitGadget wrote:
Show 5 quoted lines
> From: Seija Kijin <doremylover123@gmail.com> > > If it is known that an int is either 1 or 0, > doing an exclusive or to switch instead of a > modulus makes more sense and is more efficient.
Quite frankly, this doesn't seem like an improvement to me. It makes the code much less readable, more error-prone, and may even end up producing code that isn't portable.
Regarding the efficiency, such optimizations may be perfectly fine as a trade-off in some critical paths, but these cases don't seem like that.
Show 82 quoted lines
> Signed-off-by: Seija Kijin doremylover123@gmail.com
> ---
> Use ^=1 to toggle between 0 and 1
>
> If it is known that an int is either 1 or 0, doing an exclusive or
> to
> switch instead of a modulus makes more sense and is more efficient.
>
> Signed-off-by: Seija Kijin doremylover123@gmail.com
>
> Published-As:
> https://github.com/gitgitgadget/git/releases/tag/pr-git-1620%2FAtariDreams%2Fbuffer-v1
> Fetch-It-Via: git fetch https://github.com/gitgitgadget/git
> pr-git-1620/AtariDreams/buffer-v1
> Pull-Request: https://github.com/git/git/pull/1620
>
> builtin/fast-export.c | 4 ++--
> diff.c | 2 +-
> ident.c | 2 +-
> t/helper/test-path-utils.c | 2 +-
> 4 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/builtin/fast-export.c b/builtin/fast-export.c
> index 70aff515acb..f9f2c9dd850 100644
> --- a/builtin/fast-export.c
> +++ b/builtin/fast-export.c
> @@ -593,8 +593,8 @@ static void anonymize_ident_line(const char **beg,
> const char **end)
> struct ident_split split;
> const char *end_of_header;
>
> - out = &buffers[which_buffer++];
> - which_buffer %= ARRAY_SIZE(buffers);
> + out = &buffers[which_buffer];
> + which_buffer ^= 1;
> strbuf_reset(out);
>
> /* skip "committer", "author", "tagger", etc */
> diff --git a/diff.c b/diff.c
> index 2c602df10a3..91842b54753 100644
> --- a/diff.c
> +++ b/diff.c
> @@ -1191,7 +1191,7 @@ static void mark_color_as_moved(struct
> diff_options *o,
> &pmb_nr);
>
> if (contiguous && pmb_nr && moved_symbol == l->s)
> - flipped_block = (flipped_block + 1) % 2;
> + flipped_block ^= 1;
> else
> flipped_block = 0;
>
> diff --git a/ident.c b/ident.c
> index cc7afdbf819..188826eed63 100644
> --- a/ident.c
> +++ b/ident.c
> @@ -459,7 +459,7 @@ const char *fmt_ident(const char *name, const char
> *email,
> int want_name = !(flag & IDENT_NO_NAME);
>
> struct strbuf *ident = &ident_pool[index];
> - index = (index + 1) % ARRAY_SIZE(ident_pool);
> + index ^= 1;
>
> if (!email) {
> if (whose_ident == WANT_AUTHOR_IDENT && git_author_email.len)
> diff --git a/t/helper/test-path-utils.c b/t/helper/test-path-utils.c
> index 70396fa3845..241136148a5 100644
> --- a/t/helper/test-path-utils.c
> +++ b/t/helper/test-path-utils.c
> @@ -185,7 +185,7 @@ static int check_dotfile(const char *x, const char
> **argv,
> int res = 0, expect = 1;
> for (; *argv; argv++) {
> if (!strcmp("--not", *argv))
> - expect = !expect;
> + expect ^= 1;
> else if (expect != (is_hfs(*argv) || is_ntfs(*argv)))
> res = error("'%s' is %s.git%s", *argv,
> expect ? "not " : "", x);
>
> base-commit: 1a87c842ece327d03d08096395969aca5e0a6996