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* [Bug target/49857] New: Put constant switch-tables into flash
@ 2011-07-26 20:50 gjl at gcc dot gnu.org
2011-07-26 20:57 ` [Bug target/49857] " eric.weddington at atmel dot com
` (13 more replies)
0 siblings, 14 replies; 15+ messages in thread
From: gjl at gcc dot gnu.org @ 2011-07-26 20:50 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49857
Summary: Put constant switch-tables into flash
Product: gcc
Version: 4.6.1
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: normal
Priority: P3
Component: target
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: gjl@gcc.gnu.org
CC: eric.weddington@atmel.com
Target: avr
Created attachment 24837
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=24837
C source with constant switch statement
For constant switches like
int sw_2 (char x)
{
switch(x)
{
case '0': return -1;
case '1': return 2;
case '2': return 3;
case '3': return 5;
case '4': return 7;
case '5': return 11;
case '6': return 13;
case '7': return 17;
case '8': return 19;
case '9': return 23;
case 'a':return 29;
case 'A':return 29;
}
return -1;
}
avr-gcc 4.6.1 generates a lookup table (-Os -mmcu=atmega8 -S -fverbose-asm)
sw_2:
subi r24,lo8(-(-49)) ; csui.0,
cpi r24,lo8(49) ; csui.0,
brsh .L3 ; ,
mov r30,r24 ; tmp50, csui.0
ldi r31,lo8(0) ; ,
subi r30,lo8(-(CSWTCH.1)) ; tmp50,
sbci r31,hi8(-(CSWTCH.1)) ; tmp50,
ld r24,Z ; tmp51, CSWTCH.1
clr r25 ; D.1929
sbrc r24,7 ; D.1929
com r25 ; D.1929
ret
.L3:
ldi r24,lo8(-1) ; D.1929,
ldi r25,hi8(-1) ; D.1929,
ret
.size sw_2, .-sw_2
.data
.type CSWTCH.1, @object
.size CSWTCH.1, 49
CSWTCH.1:
.byte 2
.byte 3
.byte 5
.byte 7
.byte 11
.byte 13
.byte 17
.byte 19
.byte 23
.byte -1
.byte -1
.byte -1
...
CSWTCH.1 is put in .data (.rodata would not be better) so that the lookup table
ends up in RAM.
The table is constant and could go into flash memory, i.e. .progmem.data.
===================================
avr-gcc -v -Os -fverbose-asm -mmcu=atmega8 -W -Wall -S foo.c # dp
-mmcu=atmega128 foo.c -save-temps -Os -c
Using built-in specs.
COLLECT_GCC=e:\WinAVR\4.6.1\bin\avr-gcc.exe
COLLECT_LTO_WRAPPER=e:/winavr/4.6.1/bin/../libexec/gcc/avr/4.6.1/lto-wrapper.exe
Target: avr
Configured with: ../../gcc.gnu.org/gcc-4_6-branch/configure --target=avr
--prefix=/local/gnu/install/gcc-4.6-mingw32 --host=i586-mingw32
--build=i686-linux-gnu --enable-languages=c,c++ --disable-nls --disable-shared
--with-dwarf2
Thread model: single
gcc version 4.6.1 20110620 (prerelease) (GCC)
GNU C (GCC) version 4.6.1 20110620 (prerelease) (avr)
compiled by GNU C version 3.3.1 (mingw special 20030804-1), GMP version
4.3.2, MPFR version 2.4.2, MPC version 0.8.2
GGC heuristics: --param ggc-min-expand=47 --param ggc-min-heapsize=32702
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Bug target/49857] Put constant switch-tables into flash
2011-07-26 20:50 [Bug target/49857] New: Put constant switch-tables into flash gjl at gcc dot gnu.org
@ 2011-07-26 20:57 ` eric.weddington at atmel dot com
2011-12-01 12:49 ` eric.weddington at atmel dot com
` (12 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: eric.weddington at atmel dot com @ 2011-07-26 20:57 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49857
Eric Weddington <eric.weddington at atmel dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Severity|normal |enhancement
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Bug target/49857] Put constant switch-tables into flash
2011-07-26 20:50 [Bug target/49857] New: Put constant switch-tables into flash gjl at gcc dot gnu.org
2011-07-26 20:57 ` [Bug target/49857] " eric.weddington at atmel dot com
@ 2011-12-01 12:49 ` eric.weddington at atmel dot com
2012-01-07 12:23 ` gjl at gcc dot gnu.org
` (11 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: eric.weddington at atmel dot com @ 2011-12-01 12:49 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49857
Eric Weddington <eric.weddington at atmel dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Last reconfirmed|2011-07-27 00:00:00 |2011-12-01
Ever Confirmed|0 |1
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Bug target/49857] Put constant switch-tables into flash
2011-07-26 20:50 [Bug target/49857] New: Put constant switch-tables into flash gjl at gcc dot gnu.org
2011-07-26 20:57 ` [Bug target/49857] " eric.weddington at atmel dot com
2011-12-01 12:49 ` eric.weddington at atmel dot com
@ 2012-01-07 12:23 ` gjl at gcc dot gnu.org
2012-01-29 16:24 ` [Bug tree-optimization/49857] " gjl at gcc dot gnu.org
` (10 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: gjl at gcc dot gnu.org @ 2012-01-07 12:23 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49857
Georg-Johann Lay <gjl at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |addr-space
Target Milestone|--- |4.8.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Bug tree-optimization/49857] Put constant switch-tables into flash
2011-07-26 20:50 [Bug target/49857] New: Put constant switch-tables into flash gjl at gcc dot gnu.org
` (2 preceding siblings ...)
2012-01-07 12:23 ` gjl at gcc dot gnu.org
@ 2012-01-29 16:24 ` gjl at gcc dot gnu.org
2012-01-29 17:42 ` [Bug rtl-optimization/49857] " steven at gcc dot gnu.org
` (9 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: gjl at gcc dot gnu.org @ 2012-01-29 16:24 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49857
Georg-Johann Lay <gjl at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Component|target |tree-optimization
--- Comment #1 from Georg-Johann Lay <gjl at gcc dot gnu.org> 2012-01-29 14:55:48 UTC ---
Changed component from "target" to "tree-optimization" because:
The code in tree-switch-conversion.c needs to be extended by, say, a target
hook that queries the backend for the right address space for the generated
lookup table, i.e. the CSWTCH.num objects.
This is needed for two reasons:
1) The data (CSWTCH.num) has to be located in the preferred section,
i.e. in Flash and not in RAM.
2) The accesses have to use the right instructions, i.e. instructions to read
from non-generic address space (Flash) and not instructions to access generic
address space (RAM).
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Bug rtl-optimization/49857] Put constant switch-tables into flash
2011-07-26 20:50 [Bug target/49857] New: Put constant switch-tables into flash gjl at gcc dot gnu.org
` (3 preceding siblings ...)
2012-01-29 16:24 ` [Bug tree-optimization/49857] " gjl at gcc dot gnu.org
@ 2012-01-29 17:42 ` steven at gcc dot gnu.org
2012-01-29 18:32 ` steven at gcc dot gnu.org
` (8 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: steven at gcc dot gnu.org @ 2012-01-29 17:42 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49857
Steven Bosscher <steven at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |steven at gcc dot gnu.org
Component|tree-optimization |rtl-optimization
--- Comment #2 from Steven Bosscher <steven at gcc dot gnu.org> 2012-01-29 17:24:32 UTC ---
Jump tables are generated in stmt.c, as part of expanding to RTL.
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Bug rtl-optimization/49857] Put constant switch-tables into flash
2011-07-26 20:50 [Bug target/49857] New: Put constant switch-tables into flash gjl at gcc dot gnu.org
` (4 preceding siblings ...)
2012-01-29 17:42 ` [Bug rtl-optimization/49857] " steven at gcc dot gnu.org
@ 2012-01-29 18:32 ` steven at gcc dot gnu.org
2013-03-22 14:45 ` jakub at gcc dot gnu.org
` (7 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: steven at gcc dot gnu.org @ 2012-01-29 18:32 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49857
Steven Bosscher <steven at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC|steven at gcc dot gnu.org |
--- Comment #3 from Steven Bosscher <steven at gcc dot gnu.org> 2012-01-29 17:51:04 UTC ---
An, no, tree-switch-conversion.c:build_one_array() must build its value_type
for elements with a specified address space.
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Bug rtl-optimization/49857] Put constant switch-tables into flash
2011-07-26 20:50 [Bug target/49857] New: Put constant switch-tables into flash gjl at gcc dot gnu.org
` (5 preceding siblings ...)
2012-01-29 18:32 ` steven at gcc dot gnu.org
@ 2013-03-22 14:45 ` jakub at gcc dot gnu.org
2013-05-31 10:59 ` jakub at gcc dot gnu.org
` (6 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: jakub at gcc dot gnu.org @ 2013-03-22 14:45 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49857
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|4.8.0 |4.8.1
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-03-22 14:44:30 UTC ---
GCC 4.8.0 is being released, adjusting target milestone.
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Bug rtl-optimization/49857] Put constant switch-tables into flash
2011-07-26 20:50 [Bug target/49857] New: Put constant switch-tables into flash gjl at gcc dot gnu.org
` (6 preceding siblings ...)
2013-03-22 14:45 ` jakub at gcc dot gnu.org
@ 2013-05-31 10:59 ` jakub at gcc dot gnu.org
2013-06-01 13:41 ` gjl at gcc dot gnu.org
` (5 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: jakub at gcc dot gnu.org @ 2013-05-31 10:59 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49857
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|4.8.1 |4.8.2
--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 4.8.1 has been released.
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Bug rtl-optimization/49857] Put constant switch-tables into flash
2011-07-26 20:50 [Bug target/49857] New: Put constant switch-tables into flash gjl at gcc dot gnu.org
` (7 preceding siblings ...)
2013-05-31 10:59 ` jakub at gcc dot gnu.org
@ 2013-06-01 13:41 ` gjl at gcc dot gnu.org
2014-04-22 11:37 ` jakub at gcc dot gnu.org
` (4 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: gjl at gcc dot gnu.org @ 2013-06-01 13:41 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49857
Georg-Johann Lay <gjl at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|4.8.2 |4.9.0
--- Comment #6 from Georg-Johann Lay <gjl at gcc dot gnu.org> ---
Bumped the milestone to 4.9
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Bug rtl-optimization/49857] Put constant switch-tables into flash
2011-07-26 20:50 [Bug target/49857] New: Put constant switch-tables into flash gjl at gcc dot gnu.org
` (8 preceding siblings ...)
2013-06-01 13:41 ` gjl at gcc dot gnu.org
@ 2014-04-22 11:37 ` jakub at gcc dot gnu.org
2014-04-22 14:30 ` gjl at gcc dot gnu.org
` (3 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: jakub at gcc dot gnu.org @ 2014-04-22 11:37 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49857
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|4.9.0 |4.9.1
--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 4.9.0 has been released
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Bug rtl-optimization/49857] Put constant switch-tables into flash
2011-07-26 20:50 [Bug target/49857] New: Put constant switch-tables into flash gjl at gcc dot gnu.org
` (9 preceding siblings ...)
2014-04-22 11:37 ` jakub at gcc dot gnu.org
@ 2014-04-22 14:30 ` gjl at gcc dot gnu.org
2015-04-22 12:06 ` jakub at gcc dot gnu.org
` (2 subsequent siblings)
13 siblings, 0 replies; 15+ messages in thread
From: gjl at gcc dot gnu.org @ 2014-04-22 14:30 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49857
Georg-Johann Lay <gjl at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P3 |P4
Target Milestone|4.9.1 |4.10.0
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Bug rtl-optimization/49857] Put constant switch-tables into flash
2011-07-26 20:50 [Bug target/49857] New: Put constant switch-tables into flash gjl at gcc dot gnu.org
` (10 preceding siblings ...)
2014-04-22 14:30 ` gjl at gcc dot gnu.org
@ 2015-04-22 12:06 ` jakub at gcc dot gnu.org
2015-07-16 9:18 ` rguenth at gcc dot gnu.org
2024-08-23 19:30 ` [Bug tree-optimization/49857] [patch] " gjl at gcc dot gnu.org
13 siblings, 0 replies; 15+ messages in thread
From: jakub at gcc dot gnu.org @ 2015-04-22 12:06 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=49857
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|5.0 |5.2
--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
GCC 5.1 has been released.
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Bug rtl-optimization/49857] Put constant switch-tables into flash
2011-07-26 20:50 [Bug target/49857] New: Put constant switch-tables into flash gjl at gcc dot gnu.org
` (11 preceding siblings ...)
2015-04-22 12:06 ` jakub at gcc dot gnu.org
@ 2015-07-16 9:18 ` rguenth at gcc dot gnu.org
2024-08-23 19:30 ` [Bug tree-optimization/49857] [patch] " gjl at gcc dot gnu.org
13 siblings, 0 replies; 15+ messages in thread
From: rguenth at gcc dot gnu.org @ 2015-07-16 9:18 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=49857
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Target Milestone|5.2 |5.3
--- Comment #9 from Richard Biener <rguenth at gcc dot gnu.org> ---
GCC 5.2 is being released, adjusting target milestone to 5.3.
^ permalink raw reply [flat|nested] 15+ messages in thread
* [Bug tree-optimization/49857] [patch] Put constant switch-tables into flash
2011-07-26 20:50 [Bug target/49857] New: Put constant switch-tables into flash gjl at gcc dot gnu.org
` (12 preceding siblings ...)
2015-07-16 9:18 ` rguenth at gcc dot gnu.org
@ 2024-08-23 19:30 ` gjl at gcc dot gnu.org
13 siblings, 0 replies; 15+ messages in thread
From: gjl at gcc dot gnu.org @ 2024-08-23 19:30 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=49857
Georg-Johann Lay <gjl at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |NEW
Resolution|WONTFIX |---
^ permalink raw reply [flat|nested] 15+ messages in thread
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-- links below jump to the message on this page --
2011-07-26 20:50 [Bug target/49857] New: Put constant switch-tables into flash gjl at gcc dot gnu.org
2011-07-26 20:57 ` [Bug target/49857] " eric.weddington at atmel dot com
2011-12-01 12:49 ` eric.weddington at atmel dot com
2012-01-07 12:23 ` gjl at gcc dot gnu.org
2012-01-29 16:24 ` [Bug tree-optimization/49857] " gjl at gcc dot gnu.org
2012-01-29 17:42 ` [Bug rtl-optimization/49857] " steven at gcc dot gnu.org
2012-01-29 18:32 ` steven at gcc dot gnu.org
2013-03-22 14:45 ` jakub at gcc dot gnu.org
2013-05-31 10:59 ` jakub at gcc dot gnu.org
2013-06-01 13:41 ` gjl at gcc dot gnu.org
2014-04-22 11:37 ` jakub at gcc dot gnu.org
2014-04-22 14:30 ` gjl at gcc dot gnu.org
2015-04-22 12:06 ` jakub at gcc dot gnu.org
2015-07-16 9:18 ` rguenth at gcc dot gnu.org
2024-08-23 19:30 ` [Bug tree-optimization/49857] [patch] " gjl at gcc dot gnu.org
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