* [Bug c/87210] [RFE] introduce build time options to zero initialize automatic stack variables
[not found] <bug-87210-4@http.gcc.gnu.org/bugzilla/>
@ 2020-04-29 18:51 ` pinskia at gcc dot gnu.org
2020-05-15 20:44 ` qinzhao at gcc dot gnu.org
` (3 subsequent siblings)
4 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2020-04-29 18:51 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87210
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |qinzhao at gcc dot gnu.org
--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 94855 has been marked as a duplicate of this bug. ***
^ permalink raw reply [flat|nested] 5+ messages in thread* [Bug c/87210] [RFE] introduce build time options to zero initialize automatic stack variables
[not found] <bug-87210-4@http.gcc.gnu.org/bugzilla/>
2020-04-29 18:51 ` [Bug c/87210] [RFE] introduce build time options to zero initialize automatic stack variables pinskia at gcc dot gnu.org
@ 2020-05-15 20:44 ` qinzhao at gcc dot gnu.org
2021-08-07 20:01 ` [Bug middle-end/87210] " pinskia at gcc dot gnu.org
` (2 subsequent siblings)
4 siblings, 0 replies; 5+ messages in thread
From: qinzhao at gcc dot gnu.org @ 2020-05-15 20:44 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87210
--- Comment #6 from qinzhao at gcc dot gnu.org ---
So, based on the previous discussion on the LLVM option
-ftrivial-auto-var-init=[uninitialized|pattern|zero]
we can see:
-ftrivial-auto-var-init=pattern
might not be a good idea due to the following:
1. performance data is not good;
2. doesn't really help improve the general situation. People see it as a
debugging tool, not a "improve code quality and improve the life of kernel
developers" tool. (Per Linus)
On the other hand,
-ftrivial-auto-var-init=zero
might be helpful to improve code quality and improve the life fo kernel
developers.
At the same time, a new variable attribute might be needed at the same time
along with -ftrivial-auto-var-init=zero:
__attribute((uninitialized)
to mark variables that are uninitialized intentionally for performance purpose.
In a summary, in GCC, we should provide:
1. add a new GCC option: -ftrivial-auto-var-init to initialize trivial auto
variable to zero.
2. provide a new attribute for variable: __attribute((uninitialized) to mark
variables that are uninitialized intentionally for performance purpose.
^ permalink raw reply [flat|nested] 5+ messages in thread* [Bug middle-end/87210] [RFE] introduce build time options to zero initialize automatic stack variables
[not found] <bug-87210-4@http.gcc.gnu.org/bugzilla/>
2020-04-29 18:51 ` [Bug c/87210] [RFE] introduce build time options to zero initialize automatic stack variables pinskia at gcc dot gnu.org
2020-05-15 20:44 ` qinzhao at gcc dot gnu.org
@ 2021-08-07 20:01 ` pinskia at gcc dot gnu.org
2021-08-07 20:04 ` pinskia at gcc dot gnu.org
2021-11-29 6:28 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-08-07 20:01 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87210
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|c |middle-end
Severity|normal |enhancement
Ever confirmed|0 |1
Last reconfirmed| |2021-08-07
Status|UNCONFIRMED |NEW
--- Comment #7 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed.
^ permalink raw reply [flat|nested] 5+ messages in thread* [Bug middle-end/87210] [RFE] introduce build time options to zero initialize automatic stack variables
[not found] <bug-87210-4@http.gcc.gnu.org/bugzilla/>
` (2 preceding siblings ...)
2021-08-07 20:01 ` [Bug middle-end/87210] " pinskia at gcc dot gnu.org
@ 2021-08-07 20:04 ` pinskia at gcc dot gnu.org
2021-11-29 6:28 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-08-07 20:04 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87210
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |rth at gcc dot gnu.org
--- Comment #8 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
*** Bug 70069 has been marked as a duplicate of this bug. ***
^ permalink raw reply [flat|nested] 5+ messages in thread* [Bug middle-end/87210] [RFE] introduce build time options to zero initialize automatic stack variables
[not found] <bug-87210-4@http.gcc.gnu.org/bugzilla/>
` (3 preceding siblings ...)
2021-08-07 20:04 ` pinskia at gcc dot gnu.org
@ 2021-11-29 6:28 ` pinskia at gcc dot gnu.org
4 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu.org @ 2021-11-29 6:28 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87210
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Target Milestone|--- |12.0
Resolution|--- |FIXED
--- Comment #9 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
-ftrivial-auto-var-init=[uninitialized|pattern|zero] Add initializations to
automatic variables.
^ permalink raw reply [flat|nested] 5+ messages in thread