--- Comment #10 from pinskia at gcc dot gnu dot org 2006-01-28 04:31
---
noreturn vs sibcall:
http://gcc.gnu.org/ml/gcc-patches/2000-10/msg00180.html
http://gcc.gnu.org/ml/gcc/2002-09/msg00211.html
PR 10837
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25957
--- Comment #9 from ak at muc dot de 2006-01-25 14:55 ---
Again the alignment wastes precious icache which is enough reason to get
rid of it. If there are a lot of such functions it will also lead to
worse paging behaviour on big programs.
Can you explain again why it was shot down? Be
--- Comment #8 from steven at gcc dot gnu dot org 2006-01-25 14:46 ---
It seems to me that not aligning jumps for known infrequent jumps may be
useful. Especially when you get so many of them as you do with ssp.
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steven at gcc dot gnu dot org changed:
What|Removed
--- Comment #7 from pinskia at gcc dot gnu dot org 2006-01-25 14:43 ---
The alignment does nothing, repeat nothing even if it is not executed that
much, it does not change anything because it is last in the function. Try
compiling more than this simple example and you will see that it a
--- Comment #6 from ak at muc dot de 2006-01-25 14:38 ---
-Os is only when there should be a trade off between size and performance.
But there isn't any performance consideration here because this code
is only executed on program abort.
(is there a button to reassign the bug to a non br
--- Comment #5 from pinskia at gcc dot gnu dot org 2006-01-25 14:33 ---
Use -Os for that.
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pinskia at gcc dot gnu dot org changed:
What|Removed |Added
Statu
--- Comment #4 from ak at muc dot de 2006-01-25 14:30 ---
Yes that's the whole point of the bug. To save code space and precious
icache.
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ak at muc dot de changed:
What|Removed |Added
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--- Comment #3 from pinskia at gcc dot gnu dot org 2006-01-25 14:21 ---
Actually you will not see the correct backtrace, you will see the function
which calls f and not f itself.
The alignment only saves instruction space it does nothing really
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pinskia at gcc dot gnu dot org chan
--- Comment #2 from ak at muc dot de 2006-01-25 14:15 ---
You're wrong. On i386 and x86-64 call and conditional jumps have the same
range.
That you're using the normal align-jumps for such uncommon code is a bug in my
opinion and that is why I opened this request. It is a waste of spac
--- Comment #1 from pinskia at gcc dot gnu dot org 2006-01-25 13:21 ---
Nope and Nope.
The alignment is because well -falign-jumps is default.
__stack_chk_fail is a noreturn function so we don't sib call it because it
would be too hard for debugging.
Second jumping directly via an indir
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