http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51111
Bug #: 51111
Summary: Optimization bug with array
Classification: Unclassified
Product: gcc
Version: 4.6.2
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: vova7...@mail.ru
Have array like void *__sys_switab_addres[65536];
this array containing pointers to functions.
│.text:000008FC main
│.text:000008FC
│.text:000008FC var_3C = -0x3C
│.text:000008FC
│.text:000008FC STMFD SP!, {R4,R5,LR}
│.text:00000900 LDR R4, =__sys_switab_addres
│.text:00000904 SUB SP, SP, #0x34
│.text:00000908 LDR R3, [R4]
│.text:0000090C LDR R5, =_ZL7MAINCSM
│.text:00000910 LDR R3, [R3,#0x518]
│.text:00000914 BLX R3
│.text:00000918 LDR R3, [R4] ;duplicate
│.text:0000091C LDR R1, =aNatalarm
│.text:00000920 LDR R3, [R3,#0x490]
│.text:00000924 ADD R0, R5, #0x28
│.text:00000928 BLX R3
│.text:0000092C LDR R3, [R4] ;duplicate
│.text:00000930 ADD R1, SP, #0x40+var_3C
│.text:00000934 MOV R2, #0
│.text:00000938 LDR R3, [R3,#0x41C]
│.text:0000093C MOV R0, R5
│.text:00000940 BLX R3
│.text:00000944 LDR R3, [R4] ;duplicate
│.text:00000948 LDR R3, [R3,#0x51C]
│.text:0000094C BLX R3
│.text:00000950 MOV R0, #0
│.text:00000954 ADD SP, SP, #0x34
│.text:00000958 LDMFD SP!, {R4,R5,PC}
can be smaller with construction like this:
LDR R4, =__sys_switab_addres
LDR R4, [R4]
...
LDR R3, [R4,#0x518]
...
LDR R3, [R4,#0x490]
...
LDR R3, [R4,#0x490]
...
LDR R3, [R4,#0x41C]
...
LDR R3, [R4,#0x51C]
