http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51374
Georg-Johann Lay <gjl at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Known to work| |4.7.0
Keywords| |wrong-code
Last reconfirmed| |2011-12-01
Component|c |rtl-optimization
CC| |gjl at gcc dot gnu.org
Host|i386-redhat-linux |
Ever Confirmed|0 |1
Summary|Volatile access reordered. |[avr] insn combine reorders
| |volatile memory accesses
Target Milestone|--- |4.6.3
Known to fail| |4.6.2
--- Comment #1 from Georg-Johann Lay <gjl at gcc dot gnu.org> 2011-12-01
09:57:16 UTC ---
Please, supply informations that are needed to reproduce bugs like explained in
http://gcc.gnu.org/bugs.html/#need when you report bugs like compiler switches
applied. Thanks.
To reprodoce, optimization must be turned on:
$ avr-gcc-4.6.2 test.c -Os -dp -S
__vector_18:
in r24,44-0x20 ; 8 *movqi/4 [length = 1]
sbis 43-0x20,4 ; 12 *sbix_branch [length = 2]
rjmp .L1
lds r24,slot.1198 ; 14 *movhi/2 [length = 4]
lds r25,slot.1198+1
ldi r18,hi8(-2) ; 15 *cmphi/5 [length = 3]
cpi r24,lo8(-2)
cpc r25,r18
brne .L1 ; 16 branch [length = 1]
ldi r24,lo8(-1) ; 18 *movhi/4 [length = 2]
ldi r25,hi8(-1)
sts slot.1198+1,r25 ; 19 *movhi/3 [length = 4]
sts slot.1198,r24
.L1:
ret ; 29 return [length = 1]
avr-gcc-4.7.0 (trunk 181838) compiles correct with -O1/2/s/3, here with -Os:
__vector_18:
in r24,0xb ; 6 movqi_insn/4 [length = 1]
in r25,0xc ; 8 movqi_insn/4 [length = 1]
sbrs r24,4 ; 11 *sbrx_branchqi [length = 2]
rjmp .L1
lds r24,slot.1321 ; 13 *movhi/3 [length = 4]
lds r25,slot.1321+1
adiw r24,2 ; 14 *cmphi/7 [length = 1]
brne .L1 ; 15 branch [length = 1]
ldi r24,lo8(-1) ; 17 *movhi/5 [length = 2]
ldi r25,lo8(-1)
sts slot.1321+1,r25 ; 18 *movhi/4 [length = 4]
sts slot.1321,r24
.L1:
ret ; 35 return [length = 1]
