https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102062
Bill Schmidt <wschmidt at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |wschmidt at gcc dot gnu.org
--- Comment #1 from Bill Schmidt <wschmidt at gcc dot gnu.org> ---
Regarding the latter question, I'm surprised it's not being done. This
behavior is controlled by -fvariable-expansion-in-unroller, which was enabled
by default for PowerPC targets a couple of releases back. You reported this
against GCC 11.2, but I'm skeptical. What options are you using?
Compiling with -O2 and current trunk, I see variable expansion kicking in, and
I also see the same base register in use in all references in the loop:
test:
.LFB0:
.cfi_startproc
.localentry test,1
slwi 4,4,1
li 10,0
li 7,0
addi 9,3,-4
extsw 4,4
andi. 6,4,0x3
addi 5,4,-1
mr 8,4
beq 0,.L9
cmpdi 0,6,1
beq 0,.L13
cmpdi 0,6,2
bne 0,.L22
.L14:
lwzu 6,4(9)
addi 4,4,-1
add 10,10,6
.L13:
lwzu 6,4(9)
cmpdi 0,4,1
add 10,10,6
beq 0,.L19
.L9:
srdi 8,8,2
mtctr 8
.L2:
lwz 4,4(9)
lwz 5,12(9)
lwz 6,8(9)
lwzu 8,16(9)
add 10,4,10
add 10,10,5
add 7,6,7
add 7,7,8
bdnz .L2
.L19:
add 3,10,7
extsw 3,3
blr
.p2align 4,,15
.L22:
lwz 10,0(3)
mr 9,3
mr 4,5
b .L14
