[Bug rtl-optimization/46391] false dependencies are computed after vectorization (#2)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46391 Richard Biener changed: What|Removed |Added Status|UNCONFIRMED |RESOLVED Known to work||12.0, 7.5.0 Resolution|--- |FIXED Known to fail||4.3.5 --- Comment #5 from Richard Biener --- It is. Slightly altered testcase (to avoid unrolling on GIMPLE), with -fno-schedule-insn2 on x86_64: .L2: movdqu (%rdi,%rax), %xmm1 paddb %xmm0, %xmm1 movups %xmm1, (%rsi,%rax) movdqu 16(%rdi,%rax), %xmm2 paddb %xmm0, %xmm2 movups %xmm2, 16(%rsi,%rax) movdqu 32(%rdi,%rax), %xmm3 paddb %xmm0, %xmm3 movups %xmm3, 32(%rsi,%rax) movdqu 48(%rdi,%rax), %xmm4 paddb %xmm0, %xmm4 movups %xmm4, 48(%rsi,%rax) movdqu 64(%rdi,%rax), %xmm5 paddb %xmm0, %xmm5 movups %xmm5, 64(%rsi,%rax) movdqu 80(%rdi,%rax), %xmm6 paddb %xmm0, %xmm6 movups %xmm6, 80(%rsi,%rax) movdqu 96(%rdi,%rax), %xmm7 paddb %xmm0, %xmm7 movups %xmm7, 96(%rsi,%rax) movdqu 112(%rdi,%rax), %xmm8 paddb %xmm0, %xmm8 movups %xmm8, 112(%rsi,%rax) subq$-128, %rax cmpq$4096, %rax jne .L2 and without: .L2: movdqu (%rdi,%rax), %xmm1 movdqu 16(%rdi,%rax), %xmm2 movdqu 32(%rdi,%rax), %xmm3 movdqu 48(%rdi,%rax), %xmm4 movdqu 64(%rdi,%rax), %xmm5 paddb %xmm0, %xmm1 paddb %xmm0, %xmm2 movdqu 80(%rdi,%rax), %xmm6 movdqu 96(%rdi,%rax), %xmm7 paddb %xmm0, %xmm3 paddb %xmm0, %xmm4 movups %xmm1, (%rsi,%rax) movdqu 112(%rdi,%rax), %xmm8 paddb %xmm0, %xmm5 paddb %xmm0, %xmm6 movups %xmm2, 16(%rsi,%rax) paddb %xmm0, %xmm7 movups %xmm3, 32(%rsi,%rax) paddb %xmm0, %xmm8 movups %xmm4, 48(%rsi,%rax) movups %xmm5, 64(%rsi,%rax) movups %xmm6, 80(%rsi,%rax) movups %xmm7, 96(%rsi,%rax) movups %xmm8, 112(%rsi,%rax) subq$-128, %rax cmpq$4096, %rax jne .L2 and that's only possible if this dependence is not visible. 4.3 shows the problem still, GCC 7 doesn't.
[Bug rtl-optimization/46391] false dependencies are computed after vectorization (#2)
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46391 Andrew Pinski changed: What|Removed |Added Keywords||alias, missed-optimization Blocks||53947 --- Comment #4 from Andrew Pinski --- I suspect this has been long fixed. Referenced Bugs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947 [Bug 53947] [meta-bug] vectorizer missed-optimizations
[Bug rtl-optimization/46391] false dependencies are computed after vectorization (#2)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46391
--- Comment #3 from Roy Rosen roy.1rosen at gmail dot com 2010-11-11 08:03:57
UTC ---
It happens also on i386 with ./cc1 -O3 a.c -fdump-rtl-all -funroll-loops
-fsched-verbose=8 -fschedule-insns:
In asmcons:
(insn 16 15 17 4 a.c:5 (set (reg:SI 72 [ vect_var_.26 ])
(mem:SI (plus:SI (reg/v/f:SI 74 [ c ])
(reg:SI 70 [ ivtmp.42 ])) [0 MEM[(char * restrict)vect_p.22]+0
S4 A32])) 50 {*movsi_internal} (nil))
(insn 17 16 134 4 a.c:5 (set (mem:SI (plus:SI (reg/v/f:SI 75 [ d ])
(reg:SI 70 [ ivtmp.42 ])) [0 MEM[(char * restrict)vect_p.27]+0
S4 A32])
(reg:SI 72 [ vect_var_.26 ])) 50 {*movsi_internal} (expr_list:REG_DEAD
(reg:SI 72 [ vect_var_.26 ])
(nil)))
(insn 134 17 135 4 a.c:5 (set (reg:SI 82 [ vect_var_.26 ])
(mem:SI (plus:SI (plus:SI (reg/v/f:SI 74 [ c ])
(reg:SI 70 [ ivtmp.42 ]))
(const_int 4 [0x4])) [0 MEM[(char * restrict)vect_p.22]+0 S4
A32])) 50 {*movsi_internal} (nil))
and in sched1:
;; ==
;; -- basic block 4 from 16 to 198 -- before reload
;; ==
;; --- forward dependences:
;; --- Region Dependences --- b 4 bb 0
;; insn codebb dep prio cost reservation
;; -- --- ---
;; 1650 4 035 4 decodern,p2: 198 196 195 185
175 165 155 145 135 17
;; 1750 4 131 1 decoder0,(p4+p3): 198 196 194
184 174 164 154 144 134
;; 13450 4 131 4 decodern,p2: 198 196 195 185
175 165 155 145 135
;; 13550 4 227 1 decoder0,(p4+p3): 198 196 194
184 174 164 154 144
There should not be any dependency between 17 (store) and 134 (load).
BTW, I failed building i386 from the current snapshot so I used an old one.
(../../gcc-4.6-20101106/gcc/config/i386/bdver1.md:528: unknown mode `V4DF'
../../gcc-4.6-20101106/gcc/config/i386/bdver1.md:528: following context is `0
r egister_operand)'
)
[Bug rtl-optimization/46391] false dependencies are computed after vectorization (#2)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46391
--- Comment #1 from Richard Guenther rguenth at gcc dot gnu.org 2010-11-09
13:18:47 UTC ---
On x86_64 restrict information is there (-fdump-tree-optimized-alias):
bb 5:
# PT = nonlocal { PARM_RESTRICT.0 } (restr)
vect_p.27_71 = c_8(D) + prolog_loop_niters.16_27;
# PT = nonlocal { PARM_RESTRICT.1 } (restr)
vect_p.32_75 = d_5(D) + prolog_loop_niters.16_27;
bb 6:
# ivtmp.52_46 = PHI ivtmp.52_31(6), 0(5)
# ivtmp.55_47 = PHI ivtmp.55_33(6), 0(5)
vect_var_.28_74 = MEM[base: vect_p.27_71, index: ivtmp.55_47, offset: 0B];
MEM[base: vect_p.32_75, index: ivtmp.55_47, offset: 0B] = vect_var_.28_74;
ivtmp.52_31 = ivtmp.52_46 + 1;
ivtmp.55_33 = ivtmp.55_47 + 16;
if (ivtmp.52_31 bnd.20_49)
goto bb 6;
else
goto bb 7;
[Bug rtl-optimization/46391] false dependencies are computed after vectorization (#2)
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46391
--- Comment #2 from Roy Rosen roy.1rosen at gmail dot com 2010-11-09 13:48:15
UTC ---
Seems to me that also on ia64 it is there but the dependecies are still wrong:
;; Function nor (nor)
nor (char * restrict c, char * restrict d)
{
long unsigned int D.2085;
long unsigned int D.2086;
vector(8) char * restrict D.2087;
void * D.2084;
long unsigned int ivtmp?52;
void * D.2071;
void * D.2070;
long unsigned int ivtmp?41;
long unsigned int ivtmp?38;
vector(8) char vect_var_?25;
long int andmask?20;
long int orptrs1?19;
long int addr2int1?18;
long int addr2int0?14;
int i;
char D.2021;
bb 2:
addr2int0?14_22 = (long int) c_8(D);
addr2int1?18_24 = (long int) d_5(D);
orptrs1?19_25 = addr2int1?18_24 | addr2int0?14_22;
andmask?20_26 = orptrs1?19_25 7;
if (andmask?20_26 == 0)
goto bb 3;
else
goto bb 5;
bb 3:
ivtmp?52_37 = (long unsigned int) c_8(D);
D.2085_32 = (long unsigned int) d_5(D);
D.2086_48 = D.2085_32 + 256;
D.2087_49 = (vector(8) char * restrict) D.2086_48;
bb 4:
# PT = nonlocal { PARM_RESTRICT?1 } (restr)
# ALIGN = 8, MISALIGN = 0
# d_43 = PHI d_44(4), d_5(D)(3)
# ivtmp?52_31 = PHI ivtmp?52_30(4), ivtmp?52_37(3)
# PT = nonlocal { PARM_RESTRICT?0 } (restr)
# ALIGN = 8, MISALIGN = 0
D.2084_33 = (void *) ivtmp?52_31;
vect_var_?25_41 = MEM[(char *)D.2084_33];
ivtmp?52_30 = ivtmp?52_31 + 8;
MEM[(char *)d_43] = vect_var_?25_41;
# PT = nonlocal { PARM_RESTRICT?1 } (restr)
d_44 = d_43 + 8;
if (d_44 != D.2087_49)
goto bb 4;
else
goto bb 7;
bb 5:
ivtmp?38_4 = (long unsigned int) c_8(D);
ivtmp?41_10 = (long unsigned int) d_5(D);
bb 6:
# i_28 = PHI 0(5), i_36(6)
# ivtmp?38_19 = PHI ivtmp?38_4(5), ivtmp?38_17(6)
# ivtmp?41_6 = PHI ivtmp?41_10(5), ivtmp?41_9(6)
# PT = nonlocal { PARM_RESTRICT?0 } (restr)
D.2070_11 = (void *) ivtmp?38_19;
D.2021_34 = MEM[(char *)D.2070_11];
ivtmp?38_17 = ivtmp?38_19 + 1;
# PT = nonlocal { PARM_RESTRICT?1 } (restr)
D.2071_13 = (void *) ivtmp?41_6;
MEM[(char *)D.2071_13] = D.2021_34;
ivtmp?41_9 = ivtmp?41_6 + 1;
i_36 = i_28 + 1;
if (i_36 != 256)
goto bb 6;
else
goto bb 7;
bb 7:
return 0;
}
