Re: [committed][nvptx] Set -misa=sm_35 by default

[Tom de Vries]

On 3/23/21 9:04 AM, Thomas Schwinge wrote:
> What is your opinion about backporting that (plus Tobias' documentation
> update, plus corresponding web 'changes.html' updates?) to release
> branches, so that nvptx offloading users may use GCC 10/9/8 with CUDA
> 11.0+?

Hmm, so you're talking about making -misa=sm_35 the default for gcc 10/9/8?

Let's see, users of the latest nvidia consumer microarchitecture: ampere
are forced to use a cuda11.0+ toolchain, which means that the sm_30
default is wrong for them.

Cuda 5.x supports both sm_30 and sm_35, so users should be fine.

Cuda 4.x supports neither sm_30 nor sm_35, so users also shouldn't
observe a difference.

There might be users of cuda 4.x or older and a specific newer driver
that supports sm_30 but not sm_35, and those will be the only ones
affected.  I think we can explicitly unsupport that scenario.

So, in conclusion, LGTM.

Thanks,
- Tom

Re: [committed][nvptx] Set -misa=sm_35 by default

[Tom de Vries]

On 3/23/21 9:04 AM, Thomas Schwinge wrote:
> From eac0d3458f38cd5bb4c930b2887a547b64b046ef Mon Sep 17 00:00:00 2001
> From: Thomas Schwinge 
> Date: Wed, 13 Jan 2021 09:04:47 +0100
> Subject: [PATCH] [nvptx] Let nvptx-as figure out the target architecture
>  [PR97348]
> 
> ... now that it has been enhanced to do so.
> 
> This is a follow-up to PR97348 commit 383400a6078d75bbfa1216c9af2c37f7e88740c9
> "[nvptx] Set -misa=sm_35 by default".
> 
>   gcc/
>   PR target/97348
>   * config/nvptx/nvptx.h (ASM_SPEC): Don't set.
>   * config/nvptx/nvptx.opt (misa): Adjust comment.
> ---
>  gcc/config/nvptx/nvptx.h   | 5 -
>  gcc/config/nvptx/nvptx.opt | 1 -
>  2 files changed, 6 deletions(-)
> 
> diff --git a/gcc/config/nvptx/nvptx.h b/gcc/config/nvptx/nvptx.h
> index 2451703e77f..1a61e6207f6 100644
> --- a/gcc/config/nvptx/nvptx.h
> +++ b/gcc/config/nvptx/nvptx.h
> @@ -29,11 +29,6 @@
>  
>  #define STARTFILE_SPEC "%{mmainkernel:crt0.o}"
>  
> -/* Default needs to be in sync with default for misa in nvptx.opt.
> -   We add a default here to work around a hard-coded sm_30 default in
> -   nvptx-as.  */
> -#define ASM_SPEC "%{misa=*:-m %*; :-m sm_35}"
> -
>  #define TARGET_CPU_CPP_BUILTINS()\
>do \
>  {\
> diff --git a/gcc/config/nvptx/nvptx.opt b/gcc/config/nvptx/nvptx.opt
> index 51363e4e276..cf7f9022663 100644
> --- a/gcc/config/nvptx/nvptx.opt
> +++ b/gcc/config/nvptx/nvptx.opt
> @@ -61,7 +61,6 @@ Enum(ptx_isa) String(sm_30) Value(PTX_ISA_SM30)
>  EnumValue
>  Enum(ptx_isa) String(sm_35) Value(PTX_ISA_SM35)
>  
> -; Default needs to be in sync with default in ASM_SPEC in nvptx.h.
>  misa=
>  Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) 
> Init(PTX_ISA_SM35)
>  Specify the version of the ptx ISA to use.
> -- 2.17.1

Hi Thomas,

Sorry for the delay.  LGTM, please apply.

Thanks,
- Tom

Re: [committed][nvptx] Set -misa=sm_35 by default

[Thomas Schwinge]

Hi Tom!

Ping, one item specifically: "backporting [...] to release branches" (see
below) -- this ping is dedicated to the upcoming GCC 10.3 release.  ;-)

On 2021-01-13T12:59:14+0100, I wrote:
> On 2020-10-09T13:56:09+0200, Tom de Vries  wrote:
>> The nvptx-as assembler verifies the ptx code using ptxas, if there's any
>> in the PATH.
>>
>> The default in the nvptx port for -misa=sm_xx is sm_30, but the ptxas of the
>> latest cuda release (11.1) no longer supports sm_30.
>>
>> Consequently we cannot build gcc against that release (although we should
>> still be able to build without any cuda release).
>>
>> Fix this by setting -misa=sm_35 by default.
>>
>> Tested check-gcc on nvptx.
>>
>> Tested libgomp on x86_64-linux with nvpx accelerator.
>>
>> Both build against cuda 9.1.
>>
>> Committed to trunk.
>
> ACK.
>
> What is your opinion about backporting that (plus Tobias' documentation
> update, plus corresponding web 'changes.html' updates?) to release
> branches, so that nvptx offloading users may use GCC 10/9/8 with CUDA
> 11.0+?
>
> I don't think losing sm_30 support is a major concern: support for sm_35
> has been introduced with PTX ISA 3.1, CUDA 5.0, driver r302.


Grüße
 Thomas


> Further:

> After quite some digression to first add a testsuite to nvptx-tools (see
>  or just
> ), which
> I found advisable generally, and then given the kinds of changes we're
> now doing :-) -- I've now prepared nvptx-as code changes as discussed in
>  "nvptx-as
> should not assume a default sm version".  (Currently testing.)

>> [nvptx] Set -misa=sm_35 by default
>
>>  PR target/97348
>>  * config/nvptx/nvptx.h (ASM_SPEC): Also pass -m to nvptx-as if
>>  default is used.
>>  * config/nvptx/nvptx.opt (misa): Init with PTX_ISA_SM35.
>
>> --- a/gcc/config/nvptx/nvptx.h
>> +++ b/gcc/config/nvptx/nvptx.h
>
>> -#define ASM_SPEC "%{misa=*:-m %*}"
>> +/* Default needs to be in sync with default for misa in nvptx.opt.
>> +   We add a default here to work around a hard-coded sm_30 default in
>> +   nvptx-as.  */
>> +#define ASM_SPEC "%{misa=*:-m %*; :-m sm_35}"
>
>> --- a/gcc/config/nvptx/nvptx.opt
>> +++ b/gcc/config/nvptx/nvptx.opt
>
>> +; Default needs to be in sync with default in ASM_SPEC in nvptx.h.
>>  misa=
>> -Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) 
>> Init(PTX_ISA_SM30)
>> +Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) 
>> Init(PTX_ISA_SM35)
>>  Specify the version of the ptx ISA to use.
>
> As I'd suggested in
>  "nvptx-as
> should not assume a default sm version", I'd then push the attached
> "[nvptx] Let nvptx-as figure out the target architecture [PR97348]" to
> GCC master branch, OK?  (Currently testing.)
>
> That one I wouldn't backport to GCC release branches, so that we don't
> require users to update nvptx-tools for these builds.
>
>
> Grüße
>  Thomas


-
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Registergericht München HRB 106955, Geschäftsführer: Thomas Heurung, Frank 
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>From eac0d3458f38cd5bb4c930b2887a547b64b046ef Mon Sep 17 00:00:00 2001
From: Thomas Schwinge 
Date: Wed, 13 Jan 2021 09:04:47 +0100
Subject: [PATCH] [nvptx] Let nvptx-as figure out the target architecture
 [PR97348]

... now that it has been enhanced to do so.

This is a follow-up to PR97348 commit 383400a6078d75bbfa1216c9af2c37f7e88740c9
"[nvptx] Set -misa=sm_35 by default".

	gcc/
	PR target/97348
	* config/nvptx/nvptx.h (ASM_SPEC): Don't set.
	* config/nvptx/nvptx.opt (misa): Adjust comment.
---
 gcc/config/nvptx/nvptx.h   | 5 -
 gcc/config/nvptx/nvptx.opt | 1 -
 2 files changed, 6 deletions(-)

diff --git a/gcc/config/nvptx/nvptx.h b/gcc/config/nvptx/nvptx.h
index 2451703e77f..1a61e6207f6 100644
--- a/gcc/config/nvptx/nvptx.h
+++ b/gcc/config/nvptx/nvptx.h
@@ -29,11 +29,6 @@
 
 #define STARTFILE_SPEC "%{mmainkernel:crt0.o}"
 
-/* Default needs to be in sync with default for misa in nvptx.opt.
-   We add a default here to work around a hard-coded sm_30 default in
-   nvptx-as.  */
-#define ASM_SPEC "%{misa=*:-m %*; :-m sm_35}"
-
 #define TARGET_CPU_CPP_BUILTINS()		\
   do		\
 {		\
diff --git a/gcc/config/nvptx/nvptx.opt b/gcc/config/nvptx/nvptx.opt
index 51363e4e276..cf7f9022663 100644
--- a/gcc/config/nvptx/nvptx.opt
+++ b/gcc/config/nvptx/nvptx.opt
@@ -61,7 +61,6 @@ Enum(ptx_isa) String(sm_30) Value(PTX_ISA_SM30)
 EnumValue
 Enum(ptx_isa) String(sm_35) Value(PTX_ISA_SM35)
 
-; Default needs to be in sync with default in ASM_SPEC in nvptx.h.
 misa=
 Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) Init(PTX_ISA_SM35)
 Specify the version of the ptx ISA to use.
-- 
2.17.1

Re: [committed][nvptx] Set -misa=sm_35 by default

[Thomas Schwinge]

Hi!

Tom, ping?


Also, I have now pushed to devel/omp/gcc-10 branch cherry-picks of Tom's
"[nvptx] Set -misa=sm_35 by default" in commit
d4b73f42df11282c7c170b55eb29cd8ff6b998d8, and Tobias' "nvptx -
invoke.texi: Update default of -misa" in commit
c77b42af4fa245ea87aee0ad55fa2b76611afb47, see attached, too.


Grüße
 Thomas


On 2021-02-05T17:10:01+0100, Thomas Schwinge  wrote:
> Hi Tom!
>
> Ping.
>
>
> Grüße
>  Thomas
>
>
> On 2021-01-22T16:23:57+0100, I wrote:
>> Hi Tom!
>>
>> Ping.
>>
>>
>> Grüße
>>  Thomas
>>
>>
>> On 2021-01-13T12:59:14+0100, I wrote:
>>> Hi Tom!
>>>
>>> On 2020-10-09T13:56:09+0200, Tom de Vries  wrote:
 The nvptx-as assembler verifies the ptx code using ptxas, if there's any
 in the PATH.

>>>
>>> After quite some digression to first add a testsuite to nvptx-tools (see
>>>  or just
>>> ), which
>>> I found advisable generally, and then given the kinds of changes we're
>>> now doing :-) -- I've now prepared nvptx-as code changes as discussed in
>>>  "nvptx-as
>>> should not assume a default sm version".  (Currently testing.)
>>>
 The default in the nvptx port for -misa=sm_xx is sm_30, but the ptxas of 
 the
 latest cuda release (11.1) no longer supports sm_30.

 Consequently we cannot build gcc against that release (although we should
 still be able to build without any cuda release).

 Fix this by setting -misa=sm_35 by default.

 Tested check-gcc on nvptx.

 Tested libgomp on x86_64-linux with nvpx accelerator.

 Both build against cuda 9.1.

 Committed to trunk.
>>>
>>> ACK.
>>>
>>> What is your opinion about backporting that (plus Tobias' documentation
>>> update, plus corresponding web 'changes.html' updates?) to release
>>> branches, so that nvptx offloading users may use GCC 10/9/8 with CUDA
>>> 11.0+?
>>>
>>> I don't think losing sm_30 support is a major concern: support for sm_35
>>> has been introduced with PTX ISA 3.1, CUDA 5.0, driver r302.
>>>
>>>
>>> Further:
>>>
 [nvptx] Set -misa=sm_35 by default
>>>
 PR target/97348
 * config/nvptx/nvptx.h (ASM_SPEC): Also pass -m to nvptx-as if
 default is used.
 * config/nvptx/nvptx.opt (misa): Init with PTX_ISA_SM35.
>>>
 --- a/gcc/config/nvptx/nvptx.h
 +++ b/gcc/config/nvptx/nvptx.h
>>>
 -#define ASM_SPEC "%{misa=*:-m %*}"
 +/* Default needs to be in sync with default for misa in nvptx.opt.
 +   We add a default here to work around a hard-coded sm_30 default in
 +   nvptx-as.  */
 +#define ASM_SPEC "%{misa=*:-m %*; :-m sm_35}"
>>>
 --- a/gcc/config/nvptx/nvptx.opt
 +++ b/gcc/config/nvptx/nvptx.opt
>>>
 +; Default needs to be in sync with default in ASM_SPEC in nvptx.h.
  misa=
 -Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) 
 Init(PTX_ISA_SM30)
 +Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) 
 Init(PTX_ISA_SM35)
  Specify the version of the ptx ISA to use.
>>>
>>> As I'd suggested in
>>>  "nvptx-as
>>> should not assume a default sm version", I'd then push the attached
>>> "[nvptx] Let nvptx-as figure out the target architecture [PR97348]" to
>>> GCC master branch, OK?  (Currently testing.)
>>>
>>> That one I wouldn't backport to GCC release branches, so that we don't
>>> require users to update nvptx-tools for these builds.
>>>
>>>
>>> Grüße
>>>  Thomas


-
Mentor Graphics (Deutschland) GmbH, Arnulfstrasse 201, 80634 München 
Registergericht München HRB 106955, Geschäftsführer: Thomas Heurung, Frank 
Thürauf
>From eac0d3458f38cd5bb4c930b2887a547b64b046ef Mon Sep 17 00:00:00 2001
From: Thomas Schwinge 
Date: Wed, 13 Jan 2021 09:04:47 +0100
Subject: [PATCH] [nvptx] Let nvptx-as figure out the target architecture
 [PR97348]

... now that it has been enhanced to do so.

This is a follow-up to PR97348 commit 383400a6078d75bbfa1216c9af2c37f7e88740c9
"[nvptx] Set -misa=sm_35 by default".

	gcc/
	PR target/97348
	* config/nvptx/nvptx.h (ASM_SPEC): Don't set.
	* config/nvptx/nvptx.opt (misa): Adjust comment.
---
 gcc/config/nvptx/nvptx.h   | 5 -
 gcc/config/nvptx/nvptx.opt | 1 -
 2 files changed, 6 deletions(-)

diff --git a/gcc/config/nvptx/nvptx.h b/gcc/config/nvptx/nvptx.h
index 2451703e77f..1a61e6207f6 100644
--- a/gcc/config/nvptx/nvptx.h
+++ b/gcc/config/nvptx/nvptx.h
@@ -29,11 +29,6 @@
 
 #define STARTFILE_SPEC "%{mmainkernel:crt0.o}"
 
-/* Default needs to be in sync with default for misa in nvptx.opt.
-   We add a default here to work around a hard-coded sm_30 default in
-   nvptx-as.  */
-#define ASM_SPEC "%{misa=*:-m %*; :-m sm_35}"
-
 #define TARGET_CPU_CPP_BUILTINS()		\
   do		\
 {		\
diff --git a/gcc/config/nvptx/nvptx.opt b/gcc/conf

Re: [committed][nvptx] Set -misa=sm_35 by default

[Thomas Schwinge]

Hi Tom!

Ping.


Grüße
 Thomas


On 2021-01-22T16:23:57+0100, I wrote:
> Hi Tom!
>
> Ping.
>
>
> Grüße
>  Thomas
>
>
> On 2021-01-13T12:59:14+0100, I wrote:
>> Hi Tom!
>>
>> On 2020-10-09T13:56:09+0200, Tom de Vries  wrote:
>>> The nvptx-as assembler verifies the ptx code using ptxas, if there's any
>>> in the PATH.
>>>
>>
>> After quite some digression to first add a testsuite to nvptx-tools (see
>>  or just
>> ), which
>> I found advisable generally, and then given the kinds of changes we're
>> now doing :-) -- I've now prepared nvptx-as code changes as discussed in
>>  "nvptx-as
>> should not assume a default sm version".  (Currently testing.)
>>
>>> The default in the nvptx port for -misa=sm_xx is sm_30, but the ptxas of the
>>> latest cuda release (11.1) no longer supports sm_30.
>>>
>>> Consequently we cannot build gcc against that release (although we should
>>> still be able to build without any cuda release).
>>>
>>> Fix this by setting -misa=sm_35 by default.
>>>
>>> Tested check-gcc on nvptx.
>>>
>>> Tested libgomp on x86_64-linux with nvpx accelerator.
>>>
>>> Both build against cuda 9.1.
>>>
>>> Committed to trunk.
>>
>> ACK.
>>
>> What is your opinion about backporting that (plus Tobias' documentation
>> update, plus corresponding web 'changes.html' updates?) to release
>> branches, so that nvptx offloading users may use GCC 10/9/8 with CUDA
>> 11.0+?
>>
>> I don't think losing sm_30 support is a major concern: support for sm_35
>> has been introduced with PTX ISA 3.1, CUDA 5.0, driver r302.
>>
>>
>> Further:
>>
>>> [nvptx] Set -misa=sm_35 by default
>>
>>> PR target/97348
>>> * config/nvptx/nvptx.h (ASM_SPEC): Also pass -m to nvptx-as if
>>> default is used.
>>> * config/nvptx/nvptx.opt (misa): Init with PTX_ISA_SM35.
>>
>>> --- a/gcc/config/nvptx/nvptx.h
>>> +++ b/gcc/config/nvptx/nvptx.h
>>
>>> -#define ASM_SPEC "%{misa=*:-m %*}"
>>> +/* Default needs to be in sync with default for misa in nvptx.opt.
>>> +   We add a default here to work around a hard-coded sm_30 default in
>>> +   nvptx-as.  */
>>> +#define ASM_SPEC "%{misa=*:-m %*; :-m sm_35}"
>>
>>> --- a/gcc/config/nvptx/nvptx.opt
>>> +++ b/gcc/config/nvptx/nvptx.opt
>>
>>> +; Default needs to be in sync with default in ASM_SPEC in nvptx.h.
>>>  misa=
>>> -Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) 
>>> Init(PTX_ISA_SM30)
>>> +Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) 
>>> Init(PTX_ISA_SM35)
>>>  Specify the version of the ptx ISA to use.
>>
>> As I'd suggested in
>>  "nvptx-as
>> should not assume a default sm version", I'd then push the attached
>> "[nvptx] Let nvptx-as figure out the target architecture [PR97348]" to
>> GCC master branch, OK?  (Currently testing.)
>>
>> That one I wouldn't backport to GCC release branches, so that we don't
>> require users to update nvptx-tools for these builds.
>>
>>
>> Grüße
>>  Thomas


-
Mentor Graphics (Deutschland) GmbH, Arnulfstrasse 201, 80634 München 
Registergericht München HRB 106955, Geschäftsführer: Thomas Heurung, Frank 
Thürauf
>From eac0d3458f38cd5bb4c930b2887a547b64b046ef Mon Sep 17 00:00:00 2001
From: Thomas Schwinge 
Date: Wed, 13 Jan 2021 09:04:47 +0100
Subject: [PATCH] [nvptx] Let nvptx-as figure out the target architecture
 [PR97348]

... now that it has been enhanced to do so.

This is a follow-up to PR97348 commit 383400a6078d75bbfa1216c9af2c37f7e88740c9
"[nvptx] Set -misa=sm_35 by default".

	gcc/
	PR target/97348
	* config/nvptx/nvptx.h (ASM_SPEC): Don't set.
	* config/nvptx/nvptx.opt (misa): Adjust comment.
---
 gcc/config/nvptx/nvptx.h   | 5 -
 gcc/config/nvptx/nvptx.opt | 1 -
 2 files changed, 6 deletions(-)

diff --git a/gcc/config/nvptx/nvptx.h b/gcc/config/nvptx/nvptx.h
index 2451703e77f..1a61e6207f6 100644
--- a/gcc/config/nvptx/nvptx.h
+++ b/gcc/config/nvptx/nvptx.h
@@ -29,11 +29,6 @@
 
 #define STARTFILE_SPEC "%{mmainkernel:crt0.o}"
 
-/* Default needs to be in sync with default for misa in nvptx.opt.
-   We add a default here to work around a hard-coded sm_30 default in
-   nvptx-as.  */
-#define ASM_SPEC "%{misa=*:-m %*; :-m sm_35}"
-
 #define TARGET_CPU_CPP_BUILTINS()		\
   do		\
 {		\
diff --git a/gcc/config/nvptx/nvptx.opt b/gcc/config/nvptx/nvptx.opt
index 51363e4e276..cf7f9022663 100644
--- a/gcc/config/nvptx/nvptx.opt
+++ b/gcc/config/nvptx/nvptx.opt
@@ -61,7 +61,6 @@ Enum(ptx_isa) String(sm_30) Value(PTX_ISA_SM30)
 EnumValue
 Enum(ptx_isa) String(sm_35) Value(PTX_ISA_SM35)
 
-; Default needs to be in sync with default in ASM_SPEC in nvptx.h.
 misa=
 Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) Init(PTX_ISA_SM35)
 Specify the version of the ptx ISA to use.
-- 
2.17.1

Re: [committed][nvptx] Set -misa=sm_35 by default

[Thomas Schwinge]

Hi Tom!

Ping.


Grüße
 Thomas


On 2021-01-13T12:59:14+0100, I wrote:
> Hi Tom!
>
> On 2020-10-09T13:56:09+0200, Tom de Vries  wrote:
>> The nvptx-as assembler verifies the ptx code using ptxas, if there's any
>> in the PATH.
>>
>
> After quite some digression to first add a testsuite to nvptx-tools (see
>  or just
> ), which
> I found advisable generally, and then given the kinds of changes we're
> now doing :-) -- I've now prepared nvptx-as code changes as discussed in
>  "nvptx-as
> should not assume a default sm version".  (Currently testing.)
>
>> The default in the nvptx port for -misa=sm_xx is sm_30, but the ptxas of the
>> latest cuda release (11.1) no longer supports sm_30.
>>
>> Consequently we cannot build gcc against that release (although we should
>> still be able to build without any cuda release).
>>
>> Fix this by setting -misa=sm_35 by default.
>>
>> Tested check-gcc on nvptx.
>>
>> Tested libgomp on x86_64-linux with nvpx accelerator.
>>
>> Both build against cuda 9.1.
>>
>> Committed to trunk.
>
> ACK.
>
> What is your opinion about backporting that (plus Tobias' documentation
> update, plus corresponding web 'changes.html' updates?) to release
> branches, so that nvptx offloading users may use GCC 10/9/8 with CUDA
> 11.0+?
>
> I don't think losing sm_30 support is a major concern: support for sm_35
> has been introduced with PTX ISA 3.1, CUDA 5.0, driver r302.
>
>
> Further:
>
>> [nvptx] Set -misa=sm_35 by default
>
>>  PR target/97348
>>  * config/nvptx/nvptx.h (ASM_SPEC): Also pass -m to nvptx-as if
>>  default is used.
>>  * config/nvptx/nvptx.opt (misa): Init with PTX_ISA_SM35.
>
>> --- a/gcc/config/nvptx/nvptx.h
>> +++ b/gcc/config/nvptx/nvptx.h
>
>> -#define ASM_SPEC "%{misa=*:-m %*}"
>> +/* Default needs to be in sync with default for misa in nvptx.opt.
>> +   We add a default here to work around a hard-coded sm_30 default in
>> +   nvptx-as.  */
>> +#define ASM_SPEC "%{misa=*:-m %*; :-m sm_35}"
>
>> --- a/gcc/config/nvptx/nvptx.opt
>> +++ b/gcc/config/nvptx/nvptx.opt
>
>> +; Default needs to be in sync with default in ASM_SPEC in nvptx.h.
>>  misa=
>> -Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) 
>> Init(PTX_ISA_SM30)
>> +Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) 
>> Init(PTX_ISA_SM35)
>>  Specify the version of the ptx ISA to use.
>
> As I'd suggested in
>  "nvptx-as
> should not assume a default sm version", I'd then push the attached
> "[nvptx] Let nvptx-as figure out the target architecture [PR97348]" to
> GCC master branch, OK?  (Currently testing.)
>
> That one I wouldn't backport to GCC release branches, so that we don't
> require users to update nvptx-tools for these builds.
>
>
> Grüße
>  Thomas


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>From eac0d3458f38cd5bb4c930b2887a547b64b046ef Mon Sep 17 00:00:00 2001
From: Thomas Schwinge 
Date: Wed, 13 Jan 2021 09:04:47 +0100
Subject: [PATCH] [nvptx] Let nvptx-as figure out the target architecture
 [PR97348]

... now that it has been enhanced to do so.

This is a follow-up to PR97348 commit 383400a6078d75bbfa1216c9af2c37f7e88740c9
"[nvptx] Set -misa=sm_35 by default".

	gcc/
	PR target/97348
	* config/nvptx/nvptx.h (ASM_SPEC): Don't set.
	* config/nvptx/nvptx.opt (misa): Adjust comment.
---
 gcc/config/nvptx/nvptx.h   | 5 -
 gcc/config/nvptx/nvptx.opt | 1 -
 2 files changed, 6 deletions(-)

diff --git a/gcc/config/nvptx/nvptx.h b/gcc/config/nvptx/nvptx.h
index 2451703e77f..1a61e6207f6 100644
--- a/gcc/config/nvptx/nvptx.h
+++ b/gcc/config/nvptx/nvptx.h
@@ -29,11 +29,6 @@
 
 #define STARTFILE_SPEC "%{mmainkernel:crt0.o}"
 
-/* Default needs to be in sync with default for misa in nvptx.opt.
-   We add a default here to work around a hard-coded sm_30 default in
-   nvptx-as.  */
-#define ASM_SPEC "%{misa=*:-m %*; :-m sm_35}"
-
 #define TARGET_CPU_CPP_BUILTINS()		\
   do		\
 {		\
diff --git a/gcc/config/nvptx/nvptx.opt b/gcc/config/nvptx/nvptx.opt
index 51363e4e276..cf7f9022663 100644
--- a/gcc/config/nvptx/nvptx.opt
+++ b/gcc/config/nvptx/nvptx.opt
@@ -61,7 +61,6 @@ Enum(ptx_isa) String(sm_30) Value(PTX_ISA_SM30)
 EnumValue
 Enum(ptx_isa) String(sm_35) Value(PTX_ISA_SM35)
 
-; Default needs to be in sync with default in ASM_SPEC in nvptx.h.
 misa=
 Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) Init(PTX_ISA_SM35)
 Specify the version of the ptx ISA to use.
-- 
2.17.1

Re: [committed][nvptx] Set -misa=sm_35 by default

[Thomas Schwinge]

Hi Tom!

On 2020-10-09T13:56:09+0200, Tom de Vries  wrote:
> The nvptx-as assembler verifies the ptx code using ptxas, if there's any
> in the PATH.
>

After quite some digression to first add a testsuite to nvptx-tools (see
 or just
), which
I found advisable generally, and then given the kinds of changes we're
now doing :-) -- I've now prepared nvptx-as code changes as discussed in
 "nvptx-as
should not assume a default sm version".  (Currently testing.)

> The default in the nvptx port for -misa=sm_xx is sm_30, but the ptxas of the
> latest cuda release (11.1) no longer supports sm_30.
>
> Consequently we cannot build gcc against that release (although we should
> still be able to build without any cuda release).
>
> Fix this by setting -misa=sm_35 by default.
>
> Tested check-gcc on nvptx.
>
> Tested libgomp on x86_64-linux with nvpx accelerator.
>
> Both build against cuda 9.1.
>
> Committed to trunk.

ACK.

What is your opinion about backporting that (plus Tobias' documentation
update, plus corresponding web 'changes.html' updates?) to release
branches, so that nvptx offloading users may use GCC 10/9/8 with CUDA
11.0+?

I don't think losing sm_30 support is a major concern: support for sm_35
has been introduced with PTX ISA 3.1, CUDA 5.0, driver r302.


Further:

> [nvptx] Set -misa=sm_35 by default

>   PR target/97348
>   * config/nvptx/nvptx.h (ASM_SPEC): Also pass -m to nvptx-as if
>   default is used.
>   * config/nvptx/nvptx.opt (misa): Init with PTX_ISA_SM35.

> --- a/gcc/config/nvptx/nvptx.h
> +++ b/gcc/config/nvptx/nvptx.h

> -#define ASM_SPEC "%{misa=*:-m %*}"
> +/* Default needs to be in sync with default for misa in nvptx.opt.
> +   We add a default here to work around a hard-coded sm_30 default in
> +   nvptx-as.  */
> +#define ASM_SPEC "%{misa=*:-m %*; :-m sm_35}"

> --- a/gcc/config/nvptx/nvptx.opt
> +++ b/gcc/config/nvptx/nvptx.opt

> +; Default needs to be in sync with default in ASM_SPEC in nvptx.h.
>  misa=
> -Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) 
> Init(PTX_ISA_SM30)
> +Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) 
> Init(PTX_ISA_SM35)
>  Specify the version of the ptx ISA to use.

As I'd suggested in
 "nvptx-as
should not assume a default sm version", I'd then push the attached
"[nvptx] Let nvptx-as figure out the target architecture [PR97348]" to
GCC master branch, OK?  (Currently testing.)

That one I wouldn't backport to GCC release branches, so that we don't
require users to update nvptx-tools for these builds.


Grüße
 Thomas


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>From eac0d3458f38cd5bb4c930b2887a547b64b046ef Mon Sep 17 00:00:00 2001
From: Thomas Schwinge 
Date: Wed, 13 Jan 2021 09:04:47 +0100
Subject: [PATCH] [nvptx] Let nvptx-as figure out the target architecture
 [PR97348]

... now that it has been enhanced to do so.

This is a follow-up to PR97348 commit 383400a6078d75bbfa1216c9af2c37f7e88740c9
"[nvptx] Set -misa=sm_35 by default".

	gcc/
	PR target/97348
	* config/nvptx/nvptx.h (ASM_SPEC): Don't set.
	* config/nvptx/nvptx.opt (misa): Adjust comment.
---
 gcc/config/nvptx/nvptx.h   | 5 -
 gcc/config/nvptx/nvptx.opt | 1 -
 2 files changed, 6 deletions(-)

diff --git a/gcc/config/nvptx/nvptx.h b/gcc/config/nvptx/nvptx.h
index 2451703e77f..1a61e6207f6 100644
--- a/gcc/config/nvptx/nvptx.h
+++ b/gcc/config/nvptx/nvptx.h
@@ -29,11 +29,6 @@
 
 #define STARTFILE_SPEC "%{mmainkernel:crt0.o}"
 
-/* Default needs to be in sync with default for misa in nvptx.opt.
-   We add a default here to work around a hard-coded sm_30 default in
-   nvptx-as.  */
-#define ASM_SPEC "%{misa=*:-m %*; :-m sm_35}"
-
 #define TARGET_CPU_CPP_BUILTINS()		\
   do		\
 {		\
diff --git a/gcc/config/nvptx/nvptx.opt b/gcc/config/nvptx/nvptx.opt
index 51363e4e276..cf7f9022663 100644
--- a/gcc/config/nvptx/nvptx.opt
+++ b/gcc/config/nvptx/nvptx.opt
@@ -61,7 +61,6 @@ Enum(ptx_isa) String(sm_30) Value(PTX_ISA_SM30)
 EnumValue
 Enum(ptx_isa) String(sm_35) Value(PTX_ISA_SM35)
 
-; Default needs to be in sync with default in ASM_SPEC in nvptx.h.
 misa=
 Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) Init(PTX_ISA_SM35)
 Specify the version of the ptx ISA to use.
-- 
2.17.1

Re: [patch, committed] nvptx - invoke.texi: Update default of -misa (was: [committed][nvptx] Set -misa=sm_35 by default)

[Tom de Vries]

On 10/12/20 1:34 PM, Tobias Burnus wrote:
> On 10/9/20 1:56 PM, Tom de Vries wrote:
> 
>> [nvptx] Set -misa=sm_35 by default
> I committed the attached follow-up commit as obvious,
> r11-3818-g91e4e16b550540723cca824b9674c7d8c43f4849

Thanks for catching this.

Thanks,
- Tom

[patch, committed] nvptx - invoke.texi: Update default of -misa (was: [committed][nvptx] Set -misa=sm_35 by default)

[Tobias Burnus]

On 10/9/20 1:56 PM, Tom de Vries wrote:


[nvptx] Set -misa=sm_35 by default

I committed the attached follow-up commit as obvious,
r11-3818-g91e4e16b550540723cca824b9674c7d8c43f4849

Tobias

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commit 91e4e16b550540723cca824b9674c7d8c43f4849
Author: Tobias Burnus 
Date:   Mon Oct 12 13:13:20 2020 +0200

nvptx - invoke.texi: Update default of -misa

Followup to commit 383400a6078d75bbfa1216c9af2c37f7e88740c9

gcc/ChangeLog
* doc/invoke.texi (nvptx's -misa): Update default to sm_35.

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index b8c807e631c..307f4f5426c 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -25593,7 +25593,7 @@ Generate code for 32-bit or 64-bit ABI.
 @opindex march
 Generate code for given the specified PTX ISA (e.g.@: @samp{sm_35}).  ISA
 strings must be lower-case.  Valid ISA strings include @samp{sm_30} and
-@samp{sm_35}.  The default ISA is sm_30.
+@samp{sm_35}.  The default ISA is sm_35.
 
 @item -mmainkernel
 @opindex mmainkernel

Re: [committed][nvptx] Set -misa=sm_35 by default

[Tom de Vries]

On 10/9/20 2:19 PM, Tobias Burnus wrote:
> Hi,
> 
> On 10/9/20 1:56 PM, Tom de Vries wrote:
>> The default in the nvptx port for -misa=sm_xx is sm_30, but the ptxas
>> of the
>> latest cuda release (11.1) no longer supports sm_30.
> 
> Interestingly, at
> https://docs.nvidia.com/cuda/parallel-thread-execution/index.html#release-notes__ptx-release-history
> 
> they still claim to support everything down to sm_10. (They talk about
> supported targets, but still.)
>

Hi,

ha, funny.  Well, ptxas is pretty convinced it doesn't want to support it ;)

>> Fix this by setting -misa=sm_35 by default.
> 
> Can you update the release notes?
> 
> The other question is whether and, if so, how we want to add support for
> newer PTX ISA versions than 3.1 = CUDA 5.0. In terms of PTX ISA itself,
> moving to 6.3 would be a great step forward but requires at least CUDA
> 10. Hence, it could either a bump of the minimal CUDA version or to have
> some way to specify the PTX version. Thoughty?

A PR is open for this: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96005.

FWIW, I'm not planning to work on this short term, my plate is pretty full.

Thanks,
- Tom

Re: [committed][nvptx] Set -misa=sm_35 by default

[Tobias Burnus]

Hi,

On 10/9/20 1:56 PM, Tom de Vries wrote:

The default in the nvptx port for -misa=sm_xx is sm_30, but the ptxas of the
latest cuda release (11.1) no longer supports sm_30.


Interestingly, at
https://docs.nvidia.com/cuda/parallel-thread-execution/index.html#release-notes__ptx-release-history
they still claim to support everything down to sm_10. (They talk about
supported targets, but still.)


Fix this by setting -misa=sm_35 by default.


Can you update the release notes?

The other question is whether and, if so, how we want to add support for
newer PTX ISA versions than 3.1 = CUDA 5.0. In terms of PTX ISA itself,
moving to 6.3 would be a great step forward but requires at least CUDA
10. Hence, it could either a bump of the minimal CUDA version or to have
some way to specify the PTX version. Thoughty?

Tobias

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[committed][nvptx] Set -misa=sm_35 by default

[Tom de Vries]

Hi,

The nvptx-as assembler verifies the ptx code using ptxas, if there's any
in the PATH.

The default in the nvptx port for -misa=sm_xx is sm_30, but the ptxas of the
latest cuda release (11.1) no longer supports sm_30.

Consequently we cannot build gcc against that release (although we should
still be able to build without any cuda release).

Fix this by setting -misa=sm_35 by default.

Tested check-gcc on nvptx.

Tested libgomp on x86_64-linux with nvpx accelerator.

Both build against cuda 9.1.

Committed to trunk.

Thanks,
- Tom

[nvptx] Set -misa=sm_35 by default

gcc/ChangeLog:

2020-10-09  Tom de Vries  

PR target/97348
* config/nvptx/nvptx.h (ASM_SPEC): Also pass -m to nvptx-as if
default is used.
* config/nvptx/nvptx.opt (misa): Init with PTX_ISA_SM35.

---
 gcc/config/nvptx/nvptx.h   | 5 -
 gcc/config/nvptx/nvptx.opt | 3 ++-
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/gcc/config/nvptx/nvptx.h b/gcc/config/nvptx/nvptx.h
index 6ebcc760771..17fe157058c 100644
--- a/gcc/config/nvptx/nvptx.h
+++ b/gcc/config/nvptx/nvptx.h
@@ -29,7 +29,10 @@
 
 #define STARTFILE_SPEC "%{mmainkernel:crt0.o}"
 
-#define ASM_SPEC "%{misa=*:-m %*}"
+/* Default needs to be in sync with default for misa in nvptx.opt.
+   We add a default here to work around a hard-coded sm_30 default in
+   nvptx-as.  */
+#define ASM_SPEC "%{misa=*:-m %*; :-m sm_35}"
 
 #define TARGET_CPU_CPP_BUILTINS()  \
   do   \
diff --git a/gcc/config/nvptx/nvptx.opt b/gcc/config/nvptx/nvptx.opt
index 75c3d54864e..d6910a96cf0 100644
--- a/gcc/config/nvptx/nvptx.opt
+++ b/gcc/config/nvptx/nvptx.opt
@@ -59,6 +59,7 @@ Enum(ptx_isa) String(sm_30) Value(PTX_ISA_SM30)
 EnumValue
 Enum(ptx_isa) String(sm_35) Value(PTX_ISA_SM35)
 
+; Default needs to be in sync with default in ASM_SPEC in nvptx.h.
 misa=
-Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) 
Init(PTX_ISA_SM30)
+Target RejectNegative ToLower Joined Enum(ptx_isa) Var(ptx_isa_option) 
Init(PTX_ISA_SM35)
 Specify the version of the ptx ISA to use.