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* [Bug rtl-optimization/71309] Copying fields within a struct followed by use results in load hit store
[not found] <bug-71309-4@http.gcc.gnu.org/bugzilla/>
@ 2020-08-04 3:12 ` cvs-commit at gcc dot gnu.org
2020-08-05 0:42 ` luoxhu at gcc dot gnu.org
1 sibling, 0 replies; 2+ messages in thread
From: cvs-commit at gcc dot gnu.org @ 2020-08-04 3:12 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71309
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Xiong Hu Luo <luoxhu@gcc.gnu.org>:
https://gcc.gnu.org/g:265d817b1eb4644c7a9613ad6920315d98e2e0a4
commit r11-2526-g265d817b1eb4644c7a9613ad6920315d98e2e0a4
Author: Xionghu Luo <luoxhu@linux.ibm.com>
Date: Mon Aug 3 22:09:15 2020 -0500
dse: Remove partial load after full store for high part access[PR71309]
v5 update as comments:
1. Move const_rhs out of loop;
2. Iterate from int size for read_mode.
This patch could optimize(works for char/short/int/void*):
6: r119:TI=[r118:DI+0x10]
7: [r118:DI]=r119:TI
8: r121:DI=[r118:DI+0x8]
=>
6: r119:TI=[r118:DI+0x10]
16: r122:DI=r119:TI#8
Final ASM will be as below without partial load after full store(stxv+ld):
ld 10,16(3)
mr 9,3
ld 3,24(3)
std 10,0(9)
std 3,8(9)
blr
It could achieve ~25% performance improvement for typical cases on
Power9. Bootstrap and regression tested on Power9-LE.
For AArch64, one ldr is replaced by mov with this patch:
ldp x2, x3, [x0, 16]
stp x2, x3, [x0]
ldr x0, [x0, 8]
=>
mov x1, x0
ldp x2, x0, [x0, 16]
stp x2, x0, [x1]
gcc/ChangeLog:
2020-08-04 Xionghu Luo <luoxhu@linux.ibm.com>
PR rtl-optimization/71309
* dse.c (find_shift_sequence): Use subreg of shifted from high part
register to avoid loading from address.
gcc/testsuite/ChangeLog:
2020-08-04 Xionghu Luo <luoxhu@linux.ibm.com>
PR rtl-optimization/71309
* gcc.target/powerpc/pr71309.c: New test.
^ permalink raw reply [flat|nested] 2+ messages in thread
* [Bug rtl-optimization/71309] Copying fields within a struct followed by use results in load hit store
[not found] <bug-71309-4@http.gcc.gnu.org/bugzilla/>
2020-08-04 3:12 ` [Bug rtl-optimization/71309] Copying fields within a struct followed by use results in load hit store cvs-commit at gcc dot gnu.org
@ 2020-08-05 0:42 ` luoxhu at gcc dot gnu.org
1 sibling, 0 replies; 2+ messages in thread
From: luoxhu at gcc dot gnu.org @ 2020-08-05 0:42 UTC (permalink / raw)
To: gcc-bugs
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71309
luoxhu at gcc dot gnu.org changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |luoxhu at gcc dot gnu.org
Resolution|--- |FIXED
Status|NEW |RESOLVED
--- Comment #5 from luoxhu at gcc dot gnu.org ---
Fixed on master.
^ permalink raw reply [flat|nested] 2+ messages in thread
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2020-08-04 3:12 ` [Bug rtl-optimization/71309] Copying fields within a struct followed by use results in load hit store cvs-commit at gcc dot gnu.org
2020-08-05 0:42 ` luoxhu at gcc dot gnu.org
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