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* [Bug optimization/14721] New: jump optimization involving a sibling call within a jump table
@ 2004-03-24 17:42 kazu at cs dot umass dot edu
2004-03-24 17:45 ` [Bug optimization/14721] " kazu at cs dot umass dot edu
` (3 more replies)
0 siblings, 4 replies; 5+ messages in thread
From: kazu at cs dot umass dot edu @ 2004-03-24 17:42 UTC (permalink / raw)
To: gcc-bugs
We could put a function address in a jump table.
void bar0 (void);
void bar1 (void);
void bar2 (void);
void bar3 (void);
void bar4 (void);
void
foo (int i)
{
switch (i)
{
case 0: bar0 (); break;
case 1: bar1 (); break;
case 2: bar2 (); break;
case 3: bar3 (); break;
case 4: bar4 (); break;
}
}
Here is what I get on i686-pc-linux-gnu.
foo:
movl 4(%esp), %eax
cmpl $4, %eax
ja .L1
jmp *.L8(,%eax,4)
.section .rodata
.align 4
.align 4
.L8:
.long .L3
.long .L4
.long .L5
.long .L6
.long .L7
.text
.p2align 2,,3
.L1:
ret
.L7:
jmp bar4
.L3:
jmp bar0
.L4:
jmp bar1
.L5:
jmp bar2
.L6:
jmp bar3
It would be nice if I can get something like:
foo:
movl 4(%esp), %eax
cmpl $4, %eax
ja .L1
jmp *.L8(,%eax,4)
.section .rodata
.align 4
.align 4
.L8:
.long bar0
.long bar1
.long bar2
.long bar3
.long bar4
.text
.p2align 2,,3
.L1:
ret
--
Summary: jump optimization involving a sibling call within a jump
table
Product: gcc
Version: 3.5.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: optimization
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: kazu at cs dot umass dot edu
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: pessimizes-code
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14721
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug optimization/14721] jump optimization involving a sibling call within a jump table
2004-03-24 17:42 [Bug optimization/14721] New: jump optimization involving a sibling call within a jump table kazu at cs dot umass dot edu
@ 2004-03-24 17:45 ` kazu at cs dot umass dot edu
2004-03-24 17:47 ` kazu at cs dot umass dot edu
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: kazu at cs dot umass dot edu @ 2004-03-24 17:45 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |pessimizes-code
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14721
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug optimization/14721] jump optimization involving a sibling call within a jump table
2004-03-24 17:42 [Bug optimization/14721] New: jump optimization involving a sibling call within a jump table kazu at cs dot umass dot edu
2004-03-24 17:45 ` [Bug optimization/14721] " kazu at cs dot umass dot edu
@ 2004-03-24 17:47 ` kazu at cs dot umass dot edu
2004-03-24 17:48 ` pinskia at gcc dot gnu dot org
2004-12-22 4:34 ` [Bug rtl-optimization/14721] " pinskia at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: kazu at cs dot umass dot edu @ 2004-03-24 17:47 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14721
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug optimization/14721] jump optimization involving a sibling call within a jump table
2004-03-24 17:42 [Bug optimization/14721] New: jump optimization involving a sibling call within a jump table kazu at cs dot umass dot edu
2004-03-24 17:45 ` [Bug optimization/14721] " kazu at cs dot umass dot edu
2004-03-24 17:47 ` kazu at cs dot umass dot edu
@ 2004-03-24 17:48 ` pinskia at gcc dot gnu dot org
2004-12-22 4:34 ` [Bug rtl-optimization/14721] " pinskia at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-03-24 17:48 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-03-24 17:48 -------
Confirmed, yes that would be nice.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever Confirmed| |1
Last reconfirmed|0000-00-00 00:00:00 |2004-03-24 17:48:16
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14721
^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug rtl-optimization/14721] jump optimization involving a sibling call within a jump table
2004-03-24 17:42 [Bug optimization/14721] New: jump optimization involving a sibling call within a jump table kazu at cs dot umass dot edu
` (2 preceding siblings ...)
2004-03-24 17:48 ` pinskia at gcc dot gnu dot org
@ 2004-12-22 4:34 ` pinskia at gcc dot gnu dot org
3 siblings, 0 replies; 5+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-12-22 4:34 UTC (permalink / raw)
To: gcc-bugs
--
What |Removed |Added
----------------------------------------------------------------------------
CC| |pinskia at gcc dot gnu dot
| |org
Last reconfirmed|2004-09-22 13:17:13 |2004-12-22 04:34:49
date| |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=14721
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2004-12-22 4:34 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2004-03-24 17:42 [Bug optimization/14721] New: jump optimization involving a sibling call within a jump table kazu at cs dot umass dot edu
2004-03-24 17:45 ` [Bug optimization/14721] " kazu at cs dot umass dot edu
2004-03-24 17:47 ` kazu at cs dot umass dot edu
2004-03-24 17:48 ` pinskia at gcc dot gnu dot org
2004-12-22 4:34 ` [Bug rtl-optimization/14721] " pinskia at gcc dot gnu dot org
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