diff mbox

[3a/4,AArch64] Add attribute for compatibility with ARM pipeline models

Message ID 5644CD34.2040601@samsung.com
State New
Headers show

Commit Message

Evandro Menezes Nov. 12, 2015, 5:32 p.m. UTC 
On 11/12/2015 09:39 AM, Evandro Menezes wrote:
> On 11/12/2015 08:55 AM, James Greenhalgh wrote:
>> On Tue, Nov 10, 2015 at 11:50:12AM -0600, Evandro Menezes wrote:
>>>     2015-11-10  Evandro Menezes <e.menezes@samsung.com>
>>>
>>>     gcc/
>>>
>>>         * config/aarch64/aarch64.md (predicated): Copy attribute from
>>>         "arm.md".
>>>
>>> This patch duplicates an attribute from arm.md so that the same
>>> pipeline model can be used for both AArch32 and AArch64.
>>>
>>> Bootstrapped on arm-unknown-linux-gnueabihf, aarch64-unknown-linux-gnu.
>>>
>>> Please, commit if it's alright.
>>>
>>> -- 
>>> Evandro Menezes
>>>
>>>
>>>  From 3b643a3c026350864713e1700dc44e4794d93809 Mon Sep 17 00:00:00 2001
>>> From: Evandro Menezes <e.menezes@samsung.com>
>>> Date: Mon, 9 Nov 2015 17:11:16 -0600
>>> Subject: [PATCH 1/2] [AArch64] Add attribute for compatibility with ARM
>>>   pipeline models
>>>
>>> gcc/
>>>     * config/aarch64/aarch64.md (predicated): Copy attribute from 
>>> "arm.md".
>>> ---
>>>   gcc/config/aarch64/aarch64.md | 5 +++++
>>>   1 file changed, 5 insertions(+)
>>>
>>> diff --git a/gcc/config/aarch64/aarch64.md 
>>> b/gcc/config/aarch64/aarch64.md
>>> index 6b08850..2bc2ff5 100644
>>> --- a/gcc/config/aarch64/aarch64.md
>>> +++ b/gcc/config/aarch64/aarch64.md
>>> @@ -195,6 +195,11 @@
>>>   ;; 1 :=: yes
>>>   (define_attr "far_branch" "" (const_int 0))
>>>   +;; [For compatibility with ARM in pipeline models]
>>> +;; Attribute that specifies whether or not the instruction is executed
>>> +;; conditionally (<C> != "AL"? "yes": "no").
>> I'm not sure this <C> != "AL" [...] part makes sense to me (thinking 
>> only
>> of AArch64, I'd understand it on AArch32 :) ) and we should document 
>> that
>> this is never set for AArch64. Could you respin with a slightly clearer
>> comment.
> Since this attribute was not described in config/arm/arm.md, I felt 
> that it needed to, but perhaps in its original place instead.  I agree 
> that I should also point out that it's strictly for compatibility with 
> AArch32 and that it never matters for AArch64.
>
> WRT the <C> thing, I was referring to the opcode fields terminology 
> used by ARM in its ISA documentation.  Perhaps it's unnecessary, yes?
>

    2015-11-12  Evandro Menezes <e.menezes@samsung.com>

    [AArch64] Add attribute for compatibility with ARM pipeline models

    gcc/

        * config/aarch64/aarch64.md (predicated): Copy attribute from
        "arm.md".
        * config/arm/arm.md (predicated): Added description.

Please, commit if it's alright.

Comments

Evandro Menezes Nov. 19, 2015, 10:05 p.m. UTC | #1 
On 11/12/2015 11:32 AM, Evandro Menezes wrote:
> On 11/12/2015 09:39 AM, Evandro Menezes wrote:
>> On 11/12/2015 08:55 AM, James Greenhalgh wrote:
>>> On Tue, Nov 10, 2015 at 11:50:12AM -0600, Evandro Menezes wrote:
>>>>     2015-11-10  Evandro Menezes <e.menezes@samsung.com>
>>>>
>>>>     gcc/
>>>>
>>>>         * config/aarch64/aarch64.md (predicated): Copy attribute from
>>>>         "arm.md".
>>>>
>>>> This patch duplicates an attribute from arm.md so that the same
>>>> pipeline model can be used for both AArch32 and AArch64.
>>>>
>>>> Bootstrapped on arm-unknown-linux-gnueabihf, 
>>>> aarch64-unknown-linux-gnu.
>>>>
>>>> Please, commit if it's alright.
>>>>
>>>> -- 
>>>> Evandro Menezes
>>>>
>>>>
>>>>  From 3b643a3c026350864713e1700dc44e4794d93809 Mon Sep 17 00:00:00 
>>>> 2001
>>>> From: Evandro Menezes <e.menezes@samsung.com>
>>>> Date: Mon, 9 Nov 2015 17:11:16 -0600
>>>> Subject: [PATCH 1/2] [AArch64] Add attribute for compatibility with 
>>>> ARM
>>>>   pipeline models
>>>>
>>>> gcc/
>>>>     * config/aarch64/aarch64.md (predicated): Copy attribute from 
>>>> "arm.md".
>>>> ---
>>>>   gcc/config/aarch64/aarch64.md | 5 +++++
>>>>   1 file changed, 5 insertions(+)
>>>>
>>>> diff --git a/gcc/config/aarch64/aarch64.md 
>>>> b/gcc/config/aarch64/aarch64.md
>>>> index 6b08850..2bc2ff5 100644
>>>> --- a/gcc/config/aarch64/aarch64.md
>>>> +++ b/gcc/config/aarch64/aarch64.md
>>>> @@ -195,6 +195,11 @@
>>>>   ;; 1 :=: yes
>>>>   (define_attr "far_branch" "" (const_int 0))
>>>>   +;; [For compatibility with ARM in pipeline models]
>>>> +;; Attribute that specifies whether or not the instruction is 
>>>> executed
>>>> +;; conditionally (<C> != "AL"? "yes": "no").
>>> I'm not sure this <C> != "AL" [...] part makes sense to me (thinking 
>>> only
>>> of AArch64, I'd understand it on AArch32 :) ) and we should document 
>>> that
>>> this is never set for AArch64. Could you respin with a slightly clearer
>>> comment.
>> Since this attribute was not described in config/arm/arm.md, I felt 
>> that it needed to, but perhaps in its original place instead.  I 
>> agree that I should also point out that it's strictly for 
>> compatibility with AArch32 and that it never matters for AArch64.
>>
>> WRT the <C> thing, I was referring to the opcode fields terminology 
>> used by ARM in its ISA documentation.  Perhaps it's unnecessary, yes?
>>
>
>    2015-11-12  Evandro Menezes <e.menezes@samsung.com>
>
>    [AArch64] Add attribute for compatibility with ARM pipeline models
>
>    gcc/
>
>        * config/aarch64/aarch64.md (predicated): Copy attribute from
>        "arm.md".
>        * config/arm/arm.md (predicated): Added description.
>
> Please, commit if it's alright.

Ping.
James Greenhalgh Nov. 20, 2015, 12:27 p.m. UTC | #2 
On Thu, Nov 12, 2015 at 11:32:36AM -0600, Evandro Menezes wrote:
> On 11/12/2015 09:39 AM, Evandro Menezes wrote:
>    2015-11-12  Evandro Menezes <e.menezes@samsung.com>
> 
>    [AArch64] Add attribute for compatibility with ARM pipeline models
> 
>    gcc/
> 
>        * config/aarch64/aarch64.md (predicated): Copy attribute from
>        "arm.md".
>        * config/arm/arm.md (predicated): Added description.
> 
> Please, commit if it's alright.

The AArch64 part of this is OK.

> From 3fa6a2bca8f3d2992b4607cff0afcc2d9caa96f4 Mon Sep 17 00:00:00 2001
> From: Evandro Menezes <e.menezes@samsung.com>
> Date: Mon, 9 Nov 2015 17:11:16 -0600
> Subject: [PATCH 1/2] [AArch64] Add attribute for compatibility with ARM
>  pipeline models
> 
> gcc/
> 	* config/aarch64/aarch64.md (predicated): Copy attribute from "arm.md".
> 	* config/arm/arm.md (predicated): Added description.
> ---
>  gcc/config/aarch64/aarch64.md | 4 ++++
>  gcc/config/arm/arm.md         | 3 +++
>  2 files changed, 7 insertions(+)
> 
> diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
> index 1586256..d46f837 100644
> --- a/gcc/config/aarch64/aarch64.md
> +++ b/gcc/config/aarch64/aarch64.md
> @@ -195,6 +195,10 @@
>  ;; 1 :=: yes
>  (define_attr "far_branch" "" (const_int 0))
>  
> +;; Strictly for compatibility with AArch32 in pipeline models, since AArch64 has
> +;; no predicated insns.
> +(define_attr "predicated" "yes,no" (const_string "no"))
> +
>  ;; -------------------------------------------------------------------
>  ;; Pipeline descriptions and scheduling
>  ;; -------------------------------------------------------------------
> diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
> index 73c3088..6bda491 100644
> --- a/gcc/config/arm/arm.md
> +++ b/gcc/config/arm/arm.md
> @@ -105,6 +105,9 @@
>  (define_attr "fpu" "none,vfp"
>    (const (symbol_ref "arm_fpu_attr")))
>  
> +; Predicated means that the insn form is conditionally executed based on a
> +; predicate.  We default to 'no' because no Thumb patterns match this rule
> +; and not all ARM insns do.

s/is conditionally executed/can be conditionally executed/ in the first
sentence. Otherwise, this looks OK to me but I can't approve the ARM part,
so you'll need to wait for a review from someone who can.

Thanks,
James

>  (define_attr "predicated" "yes,no" (const_string "no"))
>  
>  ; LENGTH of an instruction (in bytes)
> -- 
> 2.1.0.243.g30d45f7
>
Kyrylo Tkachov Nov. 20, 2015, 2:34 p.m. UTC | #3 
On 20/11/15 12:27, James Greenhalgh wrote:
> On Thu, Nov 12, 2015 at 11:32:36AM -0600, Evandro Menezes wrote:
>> On 11/12/2015 09:39 AM, Evandro Menezes wrote:
>>     2015-11-12  Evandro Menezes <e.menezes@samsung.com>
>>
>>     [AArch64] Add attribute for compatibility with ARM pipeline models
>>
>>     gcc/
>>
>>         * config/aarch64/aarch64.md (predicated): Copy attribute from
>>         "arm.md".
>>         * config/arm/arm.md (predicated): Added description.

The arm part is ok too. It's just a comment.
In the ChangeLog entry for arm.md I'd say "Add description."

Thanks,
Kyrill

>> Please, commit if it's alright.
> The AArch64 part of this is OK.
>
>>  From 3fa6a2bca8f3d2992b4607cff0afcc2d9caa96f4 Mon Sep 17 00:00:00 2001
>> From: Evandro Menezes <e.menezes@samsung.com>
>> Date: Mon, 9 Nov 2015 17:11:16 -0600
>> Subject: [PATCH 1/2] [AArch64] Add attribute for compatibility with ARM
>>   pipeline models
>>
>> gcc/
>> 	* config/aarch64/aarch64.md (predicated): Copy attribute from "arm.md".
>> 	* config/arm/arm.md (predicated): Added description.
>> ---
>>   gcc/config/aarch64/aarch64.md | 4 ++++
>>   gcc/config/arm/arm.md         | 3 +++
>>   2 files changed, 7 insertions(+)
>>
>> diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
>> index 1586256..d46f837 100644
>> --- a/gcc/config/aarch64/aarch64.md
>> +++ b/gcc/config/aarch64/aarch64.md
>> @@ -195,6 +195,10 @@
>>   ;; 1 :=: yes
>>   (define_attr "far_branch" "" (const_int 0))
>>   
>> +;; Strictly for compatibility with AArch32 in pipeline models, since AArch64 has
>> +;; no predicated insns.
>> +(define_attr "predicated" "yes,no" (const_string "no"))
>> +
>>   ;; -------------------------------------------------------------------
>>   ;; Pipeline descriptions and scheduling
>>   ;; -------------------------------------------------------------------
>> diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
>> index 73c3088..6bda491 100644
>> --- a/gcc/config/arm/arm.md
>> +++ b/gcc/config/arm/arm.md
>> @@ -105,6 +105,9 @@
>>   (define_attr "fpu" "none,vfp"
>>     (const (symbol_ref "arm_fpu_attr")))
>>   
>> +; Predicated means that the insn form is conditionally executed based on a
>> +; predicate.  We default to 'no' because no Thumb patterns match this rule
>> +; and not all ARM insns do.
> s/is conditionally executed/can be conditionally executed/ in the first
> sentence. Otherwise, this looks OK to me but I can't approve the ARM part,
> so you'll need to wait for a review from someone who can.
>
> Thanks,
> James
>
>>   (define_attr "predicated" "yes,no" (const_string "no"))
>>   
>>   ; LENGTH of an instruction (in bytes)
>> -- 
>> 2.1.0.243.g30d45f7
>>
Evandro Menezes Nov. 20, 2015, 3:55 p.m. UTC | #4 
On 11/20/2015 06:27 AM, James Greenhalgh wrote:
> On Thu, Nov 12, 2015 at 11:32:36AM -0600, Evandro Menezes wrote:
>> On 11/12/2015 09:39 AM, Evandro Menezes wrote:
>>     2015-11-12  Evandro Menezes <e.menezes@samsung.com>
>>
>>     [AArch64] Add attribute for compatibility with ARM pipeline models
>>
>>     gcc/
>>
>>         * config/aarch64/aarch64.md (predicated): Copy attribute from
>>         "arm.md".
>>         * config/arm/arm.md (predicated): Added description.
>>
>> Please, commit if it's alright.
> The AArch64 part of this is OK.
>
>>  From 3fa6a2bca8f3d2992b4607cff0afcc2d9caa96f4 Mon Sep 17 00:00:00 2001
>> From: Evandro Menezes <e.menezes@samsung.com>
>> Date: Mon, 9 Nov 2015 17:11:16 -0600
>> Subject: [PATCH 1/2] [AArch64] Add attribute for compatibility with ARM
>>   pipeline models
>>
>> gcc/
>> 	* config/aarch64/aarch64.md (predicated): Copy attribute from "arm.md".
>> 	* config/arm/arm.md (predicated): Added description.
>> ---
>>   gcc/config/aarch64/aarch64.md | 4 ++++
>>   gcc/config/arm/arm.md         | 3 +++
>>   2 files changed, 7 insertions(+)
>>
>> diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
>> index 1586256..d46f837 100644
>> --- a/gcc/config/aarch64/aarch64.md
>> +++ b/gcc/config/aarch64/aarch64.md
>> @@ -195,6 +195,10 @@
>>   ;; 1 :=: yes
>>   (define_attr "far_branch" "" (const_int 0))
>>   
>> +;; Strictly for compatibility with AArch32 in pipeline models, since AArch64 has
>> +;; no predicated insns.
>> +(define_attr "predicated" "yes,no" (const_string "no"))
>> +
>>   ;; -------------------------------------------------------------------
>>   ;; Pipeline descriptions and scheduling
>>   ;; -------------------------------------------------------------------
>> diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
>> index 73c3088..6bda491 100644
>> --- a/gcc/config/arm/arm.md
>> +++ b/gcc/config/arm/arm.md
>> @@ -105,6 +105,9 @@
>>   (define_attr "fpu" "none,vfp"
>>     (const (symbol_ref "arm_fpu_attr")))
>>   
>> +; Predicated means that the insn form is conditionally executed based on a
>> +; predicate.  We default to 'no' because no Thumb patterns match this rule
>> +; and not all ARM insns do.
> s/is conditionally executed/can be conditionally executed/ in the first
> sentence. Otherwise, this looks OK to me but I can't approve the ARM part,
> so you'll need to wait for a review from someone who can.
>
>>   (define_attr "predicated" "yes,no" (const_string "no"))
>>   
>>   ; LENGTH of an instruction (in bytes)
>> -- 
>> 2.1.0.243.g30d45f7

Actually, that would then be the existing description for the 
"predicable" attribute.  I think that this proposed description is 
correct for the "predicated" attribute.

Thank you,
Evandro Menezes Nov. 20, 2015, 3:56 p.m. UTC | #5 
On 11/20/2015 08:34 AM, Kyrill Tkachov wrote:
>
> On 20/11/15 12:27, James Greenhalgh wrote:
>> On Thu, Nov 12, 2015 at 11:32:36AM -0600, Evandro Menezes wrote:
>>> On 11/12/2015 09:39 AM, Evandro Menezes wrote:
>>>     2015-11-12  Evandro Menezes <e.menezes@samsung.com>
>>>
>>>     [AArch64] Add attribute for compatibility with ARM pipeline models
>>>
>>>     gcc/
>>>
>>>         * config/aarch64/aarch64.md (predicated): Copy attribute from
>>>         "arm.md".
>>>         * config/arm/arm.md (predicated): Added description.
>
> The arm part is ok too. It's just a comment.
> In the ChangeLog entry for arm.md I'd say "Add description."
>
> Thanks,
> Kyrill
>
>>> Please, commit if it's alright.
>> The AArch64 part of this is OK.
>>
>>>  From 3fa6a2bca8f3d2992b4607cff0afcc2d9caa96f4 Mon Sep 17 00:00:00 2001
>>> From: Evandro Menezes <e.menezes@samsung.com>
>>> Date: Mon, 9 Nov 2015 17:11:16 -0600
>>> Subject: [PATCH 1/2] [AArch64] Add attribute for compatibility with ARM
>>>   pipeline models
>>>
>>> gcc/
>>>     * config/aarch64/aarch64.md (predicated): Copy attribute from 
>>> "arm.md".
>>>     * config/arm/arm.md (predicated): Added description.
>>> ---
>>>   gcc/config/aarch64/aarch64.md | 4 ++++
>>>   gcc/config/arm/arm.md         | 3 +++
>>>   2 files changed, 7 insertions(+)
>>>
>>> diff --git a/gcc/config/aarch64/aarch64.md 
>>> b/gcc/config/aarch64/aarch64.md
>>> index 1586256..d46f837 100644
>>> --- a/gcc/config/aarch64/aarch64.md
>>> +++ b/gcc/config/aarch64/aarch64.md
>>> @@ -195,6 +195,10 @@
>>>   ;; 1 :=: yes
>>>   (define_attr "far_branch" "" (const_int 0))
>>>   +;; Strictly for compatibility with AArch32 in pipeline models, 
>>> since AArch64 has
>>> +;; no predicated insns.
>>> +(define_attr "predicated" "yes,no" (const_string "no"))
>>> +
>>>   ;; 
>>> -------------------------------------------------------------------
>>>   ;; Pipeline descriptions and scheduling
>>>   ;; 
>>> -------------------------------------------------------------------
>>> diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
>>> index 73c3088..6bda491 100644
>>> --- a/gcc/config/arm/arm.md
>>> +++ b/gcc/config/arm/arm.md
>>> @@ -105,6 +105,9 @@
>>>   (define_attr "fpu" "none,vfp"
>>>     (const (symbol_ref "arm_fpu_attr")))
>>>   +; Predicated means that the insn form is conditionally executed 
>>> based on a
>>> +; predicate.  We default to 'no' because no Thumb patterns match 
>>> this rule
>>> +; and not all ARM insns do.
>> s/is conditionally executed/can be conditionally executed/ in the first
>> sentence. Otherwise, this looks OK to me but I can't approve the ARM 
>> part,
>> so you'll need to wait for a review from someone who can.
>>
>> Thanks,
>> James
>>
>>>   (define_attr "predicated" "yes,no" (const_string "no"))
>>>     ; LENGTH of an instruction (in bytes)
>>> -- 
>>> 2.1.0.243.g30d45f7

Can you please commit it with this change in the Changelog?

Thank you,
James Greenhalgh Nov. 20, 2015, 4:16 p.m. UTC | #6 
On Fri, Nov 20, 2015 at 09:55:29AM -0600, Evandro Menezes wrote:
> On 11/20/2015 06:27 AM, James Greenhalgh wrote:
> >On Thu, Nov 12, 2015 at 11:32:36AM -0600, Evandro Menezes wrote:
> >>On 11/12/2015 09:39 AM, Evandro Menezes wrote:
> >>    2015-11-12  Evandro Menezes <e.menezes@samsung.com>
> >>
> >>    [AArch64] Add attribute for compatibility with ARM pipeline models
> >>
> >>    gcc/
> >>
> >>        * config/aarch64/aarch64.md (predicated): Copy attribute from
> >>        "arm.md".
> >>        * config/arm/arm.md (predicated): Added description.
> >>
> >>Please, commit if it's alright.
> >The AArch64 part of this is OK.
> >
> >> From 3fa6a2bca8f3d2992b4607cff0afcc2d9caa96f4 Mon Sep 17 00:00:00 2001
> >>From: Evandro Menezes <e.menezes@samsung.com>
> >>Date: Mon, 9 Nov 2015 17:11:16 -0600
> >>Subject: [PATCH 1/2] [AArch64] Add attribute for compatibility with ARM
> >>  pipeline models
> >>
> >>gcc/
> >>	* config/aarch64/aarch64.md (predicated): Copy attribute from "arm.md".
> >>	* config/arm/arm.md (predicated): Added description.
> >>---
> >>  gcc/config/aarch64/aarch64.md | 4 ++++
> >>  gcc/config/arm/arm.md         | 3 +++
> >>  2 files changed, 7 insertions(+)
> >>
> >>diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
> >>index 1586256..d46f837 100644
> >>--- a/gcc/config/aarch64/aarch64.md
> >>+++ b/gcc/config/aarch64/aarch64.md
> >>@@ -195,6 +195,10 @@
> >>  ;; 1 :=: yes
> >>  (define_attr "far_branch" "" (const_int 0))
> >>+;; Strictly for compatibility with AArch32 in pipeline models, since AArch64 has
> >>+;; no predicated insns.
> >>+(define_attr "predicated" "yes,no" (const_string "no"))
> >>+
> >>  ;; -------------------------------------------------------------------
> >>  ;; Pipeline descriptions and scheduling
> >>  ;; -------------------------------------------------------------------
> >>diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
> >>index 73c3088..6bda491 100644
> >>--- a/gcc/config/arm/arm.md
> >>+++ b/gcc/config/arm/arm.md
> >>@@ -105,6 +105,9 @@
> >>  (define_attr "fpu" "none,vfp"
> >>    (const (symbol_ref "arm_fpu_attr")))
> >>+; Predicated means that the insn form is conditionally executed based on a
> >>+; predicate.  We default to 'no' because no Thumb patterns match this rule
> >>+; and not all ARM insns do.
> >s/is conditionally executed/can be conditionally executed/ in the first
> >sentence. Otherwise, this looks OK to me but I can't approve the ARM part,
> >so you'll need to wait for a review from someone who can.
> >
> >>  (define_attr "predicated" "yes,no" (const_string "no"))
> >>  ; LENGTH of an instruction (in bytes)
> >>-- 
> >>2.1.0.243.g30d45f7
> 
> Actually, that would then be the existing description for the
> "predicable" attribute.  I think that this proposed description is
> correct for the "predicated" attribute.

Right, understood, that will teach me to pattern match up to pred and stop
reading the word.

This is fine, I've committed it on your behalf as r230666

Thanks,
James
diff mbox

Patch

From 3fa6a2bca8f3d2992b4607cff0afcc2d9caa96f4 Mon Sep 17 00:00:00 2001
From: Evandro Menezes <e.menezes@samsung.com>
Date: Mon, 9 Nov 2015 17:11:16 -0600
Subject: [PATCH 1/2] [AArch64] Add attribute for compatibility with ARM
 pipeline models

gcc/
	* config/aarch64/aarch64.md (predicated): Copy attribute from "arm.md".
	* config/arm/arm.md (predicated): Added description.
---
 gcc/config/aarch64/aarch64.md | 4 ++++
 gcc/config/arm/arm.md         | 3 +++
 2 files changed, 7 insertions(+)

diff --git a/gcc/config/aarch64/aarch64.md b/gcc/config/aarch64/aarch64.md
index 1586256..d46f837 100644
--- a/gcc/config/aarch64/aarch64.md
+++ b/gcc/config/aarch64/aarch64.md
@@ -195,6 +195,10 @@ 
 ;; 1 :=: yes
 (define_attr "far_branch" "" (const_int 0))
 
+;; Strictly for compatibility with AArch32 in pipeline models, since AArch64 has
+;; no predicated insns.
+(define_attr "predicated" "yes,no" (const_string "no"))
+
 ;; -------------------------------------------------------------------
 ;; Pipeline descriptions and scheduling
 ;; -------------------------------------------------------------------
diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md
index 73c3088..6bda491 100644
--- a/gcc/config/arm/arm.md
+++ b/gcc/config/arm/arm.md
@@ -105,6 +105,9 @@ 
 (define_attr "fpu" "none,vfp"
   (const (symbol_ref "arm_fpu_attr")))
 
+; Predicated means that the insn form is conditionally executed based on a
+; predicate.  We default to 'no' because no Thumb patterns match this rule
+; and not all ARM insns do.
 (define_attr "predicated" "yes,no" (const_string "no"))
 
 ; LENGTH of an instruction (in bytes)
-- 
2.1.0.243.g30d45f7