[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Using __builtin_expect (likely/unlikely macros)
From: |
Paul Eggert |
Subject: |
Re: Using __builtin_expect (likely/unlikely macros) |
Date: |
Sat, 20 Apr 2019 12:13:03 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 |
Eli Zaretskii wrote:
In this case the patch not only improved performance, it also made
the code smaller and in my opinion more readable: the total source
code size shrank by 1775 bytes.
I meant code in C, not the produced machine code
Yes, that's what I meant too. That is, the patch made the C code shorter.
I'm not sure how do you see that the code became more readable
It's more readable to me partly because the common case is shorter, e.g.:
-static _Noreturn void module_abort (const char *format, ...)
- ATTRIBUTE_FORMAT_PRINTF(1, 2);
+static AVOID module_abort (const char *, ...) ATTRIBUTE_FORMAT_PRINTF (1, 2);
and partly because the unusual case is more obviously unusual. For example, in:
-static _Noreturn void
+static AVOID
x_connection_closed (Display *dpy, const char *error_message, bool ioerror)
...
-static _Noreturn int
+static _Noreturn ATTRIBUTE_COLD int
x_io_error_quitter (Display *display)
the x_connection_closed closed is obviously typical (it uses the now-common
"AVOID"), whereas the x_io_error_quitter is obviously atypical (one normally
doesn't see ATTRIBUTE_COLD in .c files), and this lets the reader more-easily
see that x_io_error_quitter (a) returns 'int' and (b) never returns anything,
which makes it even more of an oddball than the usual AVOID functions are.
- Re: Using __builtin_expect (likely/unlikely macros), (continued)
- Re: Using __builtin_expect (likely/unlikely macros), Andy Moreton, 2019/04/20
- Re: Using __builtin_expect (likely/unlikely macros), Paul Eggert, 2019/04/20
- Re: Using __builtin_expect (likely/unlikely macros), Eli Zaretskii, 2019/04/20
- Re: Using __builtin_expect (likely/unlikely macros), Paul Eggert, 2019/04/20
- Re: Using __builtin_expect (likely/unlikely macros), Eli Zaretskii, 2019/04/20
- Re: Using __builtin_expect (likely/unlikely macros), Paul Eggert, 2019/04/20
- Re: Using __builtin_expect (likely/unlikely macros), Eli Zaretskii, 2019/04/20
- Re: Using __builtin_expect (likely/unlikely macros),
Paul Eggert <=
- Re: Using __builtin_expect (likely/unlikely macros), Óscar Fuentes, 2019/04/20
- Re: Using __builtin_expect (likely/unlikely macros), Paul Eggert, 2019/04/20
- Re: Using __builtin_expect (likely/unlikely macros), Óscar Fuentes, 2019/04/20
- Re: Using __builtin_expect (likely/unlikely macros), Paul Eggert, 2019/04/20