------- Comment #1 from rguenth at gcc dot gnu dot org 2010-04-22 09:07 -------
Hm, frob1 looks like
_Z5frob1RK5foo_tRS_:
.LFB18:
movss (%rdi), %xmm3
movss 4(%rdi), %xmm2
movaps %xmm3, %xmm4
movaps %xmm2, %xmm0
mulss %xmm3, %xmm4
movss 8(%rdi), %xmm1
mulss %xmm2, %xmm0
addss %xmm4, %xmm0
movaps %xmm1, %xmm4
mulss %xmm1, %xmm4
addss %xmm4, %xmm0
rsqrtss %xmm0, %xmm4
mulss %xmm4, %xmm0
mulss %xmm4, %xmm0
mulss .LC1(%rip), %xmm4
addss .LC0(%rip), %xmm0
mulss %xmm4, %xmm0
mulss %xmm0, %xmm3
mulss %xmm0, %xmm2
mulss %xmm1, %xmm0
movss %xmm3, (%rsi)
movss %xmm2, 4(%rsi)
movss %xmm0, 8(%rsi)
ret
and frob2 like
_Z5frob2RK5bar_tRS_:
.LFB19:
movss (%rdi), %xmm3
movss 4(%rdi), %xmm2
movaps %xmm3, %xmm4
movaps %xmm2, %xmm0
mulss %xmm3, %xmm4
movss 8(%rdi), %xmm1
mulss %xmm2, %xmm0
addss %xmm4, %xmm0
movaps %xmm1, %xmm4
mulss %xmm1, %xmm4
addss %xmm4, %xmm0
rsqrtss %xmm0, %xmm4
mulss %xmm4, %xmm0
mulss %xmm4, %xmm0
mulss .LC1(%rip), %xmm4
addss .LC0(%rip), %xmm0
mulss %xmm4, %xmm0
mulss %xmm0, %xmm3
mulss %xmm0, %xmm2
mulss %xmm1, %xmm0
movss %xmm3, -24(%rsp)
movss %xmm2, -20(%rsp)
movq -24(%rsp), %rax
movss %xmm0, -16(%rsp)
movq %rax, (%rsi)
movl -16(%rsp), %eax
movl %eax, 8(%rsi)
ret
so it's an aggregate copy that is not scalarized in frob2:
b_1(D)->x = D.2444_20;
b_1(D)->y = D.2443_19;
b_1(D)->z = D.2442_18;
return;
vs.
D.2464.m[0] = D.2473_20;
D.2464.m[1] = D.2472_19;
D.2464.m[2] = D.2471_18;
*b_1(D) = D.2464;
return;
all inlining happens during early inlining and frob1 and frob2 are reasonably
similar after early inlining.
But then we have early SRA which does
;; Function void frob1(const foo_t&, foo_t&) (_Z5frob1RK5foo_tRS_)
Candidate (2452): D.2452
Candidate (2434): v
Candidate (2435): D.2435
Will attempt to totally scalarize D.2435 (UID: 2435):
Will attempt to totally scalarize D.2452 (UID: 2452):
Marking v offset: 0, size: 32: to be replaced.
Marking v offset: 32, size: 32: to be replaced.
Marking v offset: 64, size: 32: to be replaced.
...
;; Function void frob2(const bar_t&, bar_t&) (_Z5frob2RK5bar_tRS_)
Candidate (2481): D.2481
Candidate (2464): D.2464
Candidate (2463): v
Marking v offset: 0, size: 32: to be replaced.
Marking v offset: 32, size: 32: to be replaced.
Marking v offset: 64, size: 32: to be replaced.
...
! Disqualifying D.2464 - No scalar replacements to be created.
so it doesn't consider the struct with the array for total scalarization
for some reason. Martin?
--
rguenth at gcc dot gnu dot org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jamborm at gcc dot gnu dot
| |org
Status|UNCONFIRMED |NEW
Ever Confirmed|0 |1
Last reconfirmed|0000-00-00 00:00:00 |2010-04-22 09:07:40
date| |
Summary|4.5.0 regression, array vs |[4.5 Regression] array vs
|members, dead code removal |members, total scalarization
|issues |issues
Target Milestone|--- |4.5.1
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43846
