https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63281
--- Comment #17 from Jiu Fu Guo <guojiufu at gcc dot gnu.org> ---
One thing, I'm wondering, is if it is really 'slow' using instructions to build
the const (even with 5 insns).
For example, there seems no big difference in runtime between the below two
pieces of code on a real machine.
1.
foo:
.LFB0:
.cfi_startproc
std %r31,-8(%r1)
.cfi_offset 31, -8
li %r12,2
li %r31,1
li %r0,3
li %r11,4
std %r31,0(%r3)
std %r12,0(%r4)
std %r0,0(%r5)
std %r11,0(%r6)
std %r31,0(%r7)
std %r12,0(%r8)
ld %r31,-8(%r1)
std %r0,0(%r9)
std %r11,0(%r10)
.cfi_restore 31
blr
2
foo:
.LFB0:
.cfi_startproc
std 31,-8(1)
.cfi_offset 31, -8
li 11,0
li 31,0
li 12,0
ori 11,11,0x8000
ori 31,31,0x8000
ori 12,12,0x8000
sldi 11,11,32
sldi 31,31,32
sldi 12,12,32
oris 11,11,0x410
oris 31,31,0x410
oris 12,12,0x410
ori 11,11,0x1
ori 31,31,0x3
ori 12,12,0x5
li 0,0
std 11,0(3)
std 31,0(4)
li 3,0
li 4,0
std 12,0(5)
li 5,0
ori 0,0,0x8000
ld 31,-8(1)
ori 3,3,0x8000
ori 4,4,0x8000
ori 5,5,0x8000
sldi 0,0,32
sldi 3,3,32
sldi 4,4,32
sldi 5,5,32
oris 0,0,0x410
oris 3,3,0x410
oris 4,4,0x410
oris 5,5,0x410
ori 0,0,0x7
addi 11,11,5
ori 3,3,0xa
ori 4,4,0xe
ori 5,5,0xc
std 0,0(6)
std 11,0(7)
std 3,0(8)
std 4,0(9)
std 5,0(10)
.cfi_restore 31
blr
