From: Evandro Menezes <e.menezes@samsung.com>
To: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
Cc: "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>,
nd <nd@arm.com>, Marcus Shawcroft <Marcus.Shawcroft@arm.com>,
Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>,
James Greenhalgh <James.Greenhalgh@arm.com>
Subject: Re: [PATCH][AArch64] Replace insn to zero up DF register
Date: Wed, 27 Jan 2016 23:14:00 -0000 [thread overview]
Message-ID: <56A94F35.8000000@samsung.com> (raw)
In-Reply-To: <AM3PR08MB0088B55381337130367380A383C40@AM3PR08MB0088.eurprd08.prod.outlook.com>
[-- Attachment #1: Type: text/plain, Size: 2242 bytes --]
On 01/22/16 07:52, Wilco Dijkstra wrote:
> On 12/16/2015 03:30 PM, Evandro Menezes wrote:
>> On 10/30/2015 05:24 AM, Marcus Shawcroft wrote:
>>
>> On 20 October 2015 at 00:40, Evandro Menezes <e.menezes@samsung.com> wrote:
>>
>> In the existing targets, it seems that it's always faster to zero up a DF
>>
>> register with "movi %d0, #0" instead of "fmov %d0, xzr".
>>
>> This patch modifies the respective pattern.
>>
>>
>> Hi Evandro,
>>
>> This patch changes the generic, u architecture independent instruction
>> selection. The ARM ARM (C3.5.3) makes a specific recommendation about
>> the choice of instruction in this situation and the current
>> implementation in GCC follows that recommendation. Wilco has also
>> picked up on this issue he has the same patch internal to ARM along
>> with an ongoing discussion with ARM architecture folk regarding this
>> recommendation. I'm reluctant to take this patch right now on the
>> basis that it runs contrary to ARM ARM recommendation pending the
>> conclusion of Wilco's discussion with ARM architecture folk.
>>
>>
>> Have you had a chance to discuss this internally further?
> Yes, it was decided to remove the recommendation from future ARM ARM's.
>
> Several review comments on your patch (https://patchwork.ozlabs.org/patch/532736):
>
> * This should be added to movhf, movsf and movdf - movtf already does this.
> * It is important to set the "fp" and "simd" attributes so that the movi variant can
> only be selected if it is available.
>
Hi, Wilco.
2016-01-27 Evandro Menezes <e.menezes@samsung.com>
Replace insn to zero up SIMD registers
gcc/
* config/aarch64/aarch64.md
(*movhf_aarch64): Add "movi %0, #0" to zero up register.
(*movsf_aarch64): Likewise.
(*movdf_aarch64): Likewise.
When this decision is final, methinks that this patch would be close to
addressing this change.
I have a question though: is it necessary to add the "fp" and "simd"
attributes to both movsf_aarch64 and movdf_aarch64 as well?
Thank you,
--
Evandro Menezes
[-- Attachment #2: 0001-Replace-insn-to-zero-up-SIMD-registers.patch --]
[-- Type: text/x-patch, Size: 3488 bytes --]
From b390d411b56cfcdedf4601d0487baf1ef84e79ab Mon Sep 17 00:00:00 2001
From: Evandro Menezes <e.menezes@samsung.com>
Date: Mon, 19 Oct 2015 18:31:48 -0500
Subject: [PATCH] Replace insn to zero up SIMD registers
gcc/
* config/aarch64/aarch64.md
(*movhf_aarch64): Add "movi %0, #0" to zero up register.
(*movsf_aarch64): Likewise.
(*movdf_aarch64): Likewise.
---
gcc/config/aarch64/aarch64.md | 25 ++++++++++++++-----------
1 file changed, 14 insertions(+), 11 deletions(-)
diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index f6c8eb1..43a3854 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -1164,64 +1164,67 @@
operands[1] = force_reg (<MODE>mode, operands[1]);
}
)
(define_insn "*movhf_aarch64"
- [(set (match_operand:HF 0 "nonimmediate_operand" "=w, ?r,w,w,m,r,m ,r")
- (match_operand:HF 1 "general_operand" "?rY, w,w,m,w,m,rY,r"))]
+ [(set (match_operand:HF 0 "nonimmediate_operand" "=w,w,?r,w,w,m,r,m ,r")
+ (match_operand:HF 1 "general_operand" "?r,Y, w,w,m,w,m,rY,r"))]
"TARGET_FLOAT && (register_operand (operands[0], HFmode)
|| aarch64_reg_or_fp_zero (operands[1], HFmode))"
"@
mov\\t%0.h[0], %w1
+ movi\\t%0.8h, #0
umov\\t%w0, %1.h[0]
mov\\t%0.h[0], %1.h[0]
ldr\\t%h0, %1
str\\t%h1, %0
ldrh\\t%w0, %1
strh\\t%w1, %0
mov\\t%w0, %w1"
- [(set_attr "type" "neon_from_gp,neon_to_gp,neon_move,\
+ [(set_attr "type" "neon_from_gp,neon_move,neon_to_gp,neon_move,\
f_loads,f_stores,load1,store1,mov_reg")
- (set_attr "simd" "yes,yes,yes,*,*,*,*,*")
- (set_attr "fp" "*,*,*,yes,yes,*,*,*")]
+ (set_attr "simd" "yes,yes,yes,yes,*,*,*,*,*")
+ (set_attr "fp" "*,*,*,*,yes,yes,*,*,*")]
)
(define_insn "*movsf_aarch64"
- [(set (match_operand:SF 0 "nonimmediate_operand" "=w, ?r,w,w ,w,m,r,m ,r")
- (match_operand:SF 1 "general_operand" "?rY, w,w,Ufc,m,w,m,rY,r"))]
+ [(set (match_operand:SF 0 "nonimmediate_operand" "=w,w,?r,w,w ,w,m,r,m ,r")
+ (match_operand:SF 1 "general_operand" "?r,Y, w,w,Ufc,m,w,m,rY,r"))]
"TARGET_FLOAT && (register_operand (operands[0], SFmode)
|| aarch64_reg_or_fp_zero (operands[1], SFmode))"
"@
fmov\\t%s0, %w1
+ movi\\t%0.4s, #0
fmov\\t%w0, %s1
fmov\\t%s0, %s1
fmov\\t%s0, %1
ldr\\t%s0, %1
str\\t%s1, %0
ldr\\t%w0, %1
str\\t%w1, %0
mov\\t%w0, %w1"
- [(set_attr "type" "f_mcr,f_mrc,fmov,fconsts,\
+ [(set_attr "type" "f_mcr,neon_move,f_mrc,fmov,fconsts,\
f_loads,f_stores,load1,store1,mov_reg")]
)
(define_insn "*movdf_aarch64"
- [(set (match_operand:DF 0 "nonimmediate_operand" "=w, ?r,w,w ,w,m,r,m ,r")
- (match_operand:DF 1 "general_operand" "?rY, w,w,Ufc,m,w,m,rY,r"))]
+ [(set (match_operand:DF 0 "nonimmediate_operand" "=w,w,?r,w,w ,w,m,r,m ,r")
+ (match_operand:DF 1 "general_operand" "?r,Y, w,w,Ufc,m,w,m,rY,r"))]
"TARGET_FLOAT && (register_operand (operands[0], DFmode)
|| aarch64_reg_or_fp_zero (operands[1], DFmode))"
"@
fmov\\t%d0, %x1
+ movi\\t%d0, #0
fmov\\t%x0, %d1
fmov\\t%d0, %d1
fmov\\t%d0, %1
ldr\\t%d0, %1
str\\t%d1, %0
ldr\\t%x0, %1
str\\t%x1, %0
mov\\t%x0, %x1"
- [(set_attr "type" "f_mcr,f_mrc,fmov,fconstd,\
+ [(set_attr "type" "f_mcr,neon_move,f_mrc,fmov,fconstd,\
f_loadd,f_stored,load1,store1,mov_reg")]
)
(define_insn "*movtf_aarch64"
[(set (match_operand:TF 0
--
2.6.3
next prev parent reply other threads:[~2016-01-27 23:14 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-22 13:52 Wilco Dijkstra
2016-01-27 23:14 ` Evandro Menezes [this message]
2016-02-26 12:37 ` Wilco Dijkstra
2016-02-26 22:43 ` Evandro Menezes
2016-02-29 18:07 ` Wilco Dijkstra
2016-02-29 23:11 ` Evandro Menezes
2016-03-01 19:02 ` Wilco Dijkstra
2016-03-01 19:08 ` Evandro Menezes
2016-03-09 21:36 ` Evandro Menezes
2016-03-10 13:23 ` James Greenhalgh
2016-03-10 16:27 ` Evandro Menezes
2016-03-10 16:32 ` Evandro Menezes
2016-03-10 16:37 ` James Greenhalgh
2016-04-25 19:20 ` [PATCH][AArch64] Replace insn to zero up SIMD registers Evandro Menezes
2016-04-26 13:25 ` Wilco Dijkstra
2016-04-27 19:55 ` Evandro Menezes
-- strict thread matches above, loose matches on Subject: below --
2015-10-19 23:41 [PATCH][AArch64] Replace insn to zero up DF register Evandro Menezes
2015-10-19 23:52 ` Andrew Pinski
2015-10-20 0:33 ` Andrew Pinski
2015-10-20 14:46 ` Andrew Pinski
2015-10-28 18:49 ` Evandro Menezes
2015-10-30 10:26 ` Marcus Shawcroft
2015-11-09 22:59 ` Evandro Menezes
2015-12-03 21:01 ` Evandro Menezes
2015-11-19 22:01 ` Evandro Menezes
2015-12-16 21:30 ` Evandro Menezes
2016-01-13 0:06 ` Evandro Menezes
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