llvm dev - Jan 2017 - LLVMTargetMachine with optimization level passed from clang.

Here is a problem scenario.

I want to enable a backend pass at -O2 or above.
if (TM->getOptLevel() >= CodeGenOpt::Default)
    addPass(&xxxxx);

This pass will be run at -O1 too since clang is creating the TargetMachine with
CodeGenOpt::Default for -O1.

--Sumanth G
-----Original Message-----
From: mehdi.amini at apple.com [mailto:mehdi.amini at apple.com] 
Sent: Friday, January 6, 2017 12:37 PM
To: Sumanth Gundapaneni <sgundapa at codeaurora.org>
Cc: jpaquette at apple.com; LLVM Developers <llvm-dev at lists.llvm.org>
Subject: Re: [llvm-dev] LLVMTargetMachine with optimization level passed from
clang.

> On Jan 6, 2017, at 7:59 AM, Sumanth Gundapaneni via llvm-dev <llvm-dev
at lists.llvm.org> wrote:
> 
> getOptLevel() gets the level from TargetMachine which is created by 
> the Backendutil in clang with either "Default", "None"
or "Aggressive". Threre is no correspondence for "Less".
> This boils down to , if I pass "-O1", the Target Machine is
created with CodeGenOpt::Default.
I don’t see why is it a problem? That’s why I asked earlier if you want it on
for O1 *and above* or only O1.
You just have to enable it when CodeGenOpt is Default or above (or disabling it
when CodeGenOpt::None), or did I miss something?

—
Mehdi

> 
> I am available on IRC @ sgundapa.
> 
> -----Original Message-----
> From: jpaquette at apple.com [mailto:jpaquette at apple.com] 
> Sent: Thursday, January 5, 2017 12:24 PM
> To: sgundapa at codeaurora.org
> Cc: LLVM Developers <llvm-dev at lists.llvm.org>
> Subject: Re: [llvm-dev] LLVMTargetMachine with optimization level passed
from clang.
> 
> Most of the stuff you’re looking for lives in TargetPassConfig.cpp. There
are a few examples of how you might do it that live in there too.
> 
> What it comes down to is finding the place you want your pass to live and
sticking in some logic like this in there:
> 
> if (getOptLevel() != CodeGenOpt::None)
>    addPass(&MyPassID);
> 
> A lot of passes are added in just TargetPassConfig::addMachinePasses(), but
some live in more specialized areas like, for the sake of example,
TargetPassConfig::addMachineLateOptimization(). You can add it wherever seems
best for your specific pass.
> 
> Hope that helps!
> 
> Jessica Paquette
> 
>> On Jan 5, 2017, at 8:12 AM, via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
>> 
>> I want the optimization to be turned on at -O1 and above.
>> In my case, it is a target independent back-end pass. (Eg: 
>> MachinePipeliner)
>> 
>> 
>> On 2017-01-04 18:10, Mehdi Amini wrote:
>>>> On Jan 4, 2017, at 4:03 PM, Sumanth Gundapaneni via llvm-dev 
>>>> <llvm-dev at lists.llvm.org> wrote:
>>>> I see the BackendUtil.cpp of Clang creates the TargetMachine
with
>>>> the optimization level based on below mentioned logic 
>>>> CodeGenOpt::Level OptLevel = CodeGenOpt::Default; switch 
>>>> (CodeGenOpts.OptimizationLevel) {
>>>> default: break;
>>>> case 0: OptLevel = CodeGenOpt::None; break; case 3: OptLevel = 
>>>> CodeGenOpt::Aggressive; break; } As per my understanding, the 
>>>> correspondence between optimization level and CodeGenOpt is as
below
>>>> O0  -  none
>>>> O1  -  less
>>>> O2 -   default
>>>> O3  -  aggressive
>>>> My goal is to turn on a target dependent codegen optimization
at
>>>> –O1(less).
>>> Apparently “less” is not used by clang, do you want your
optimization
>>> to be turned on for O1 *and above* or just for O1 specifically?
>>> Also what kind of optimization is this? A SelectionDAG combine or a
>>> specific pass? If it is a pass, is it IR or MIR?
>>> —
>>> Mehdi
>>>> The TargetMachine is constructed with “CodeGenOpt::Default”. Is
>>>> there a way I could do this in LLVM ? What is the standard way
of
>>>> doing this ? Also, the code in BackendUtil.cpp seem somewhat
offbeat
>>>> to me.
>>>> --Sumanth G
>>>> _______________________________________________
>>>> LLVM Developers mailing list
>>>> llvm-dev at lists.llvm.org
>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> 
> 
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

> On Jan 6, 2017, at 10:56 AM, Sumanth Gundapaneni <sgundapa at
codeaurora.org> wrote:
> 
> Here is a problem scenario.
> 
> I want to enable a backend pass at -O2 or above.
> if (TM->getOptLevel() >= CodeGenOpt::Default)
>    addPass(&xxxxx);
> 
> This pass will be run at -O1 too since clang is creating the TargetMachine
with CodeGenOpt::Default for -O1.
Right, you can’t.
(You wrote yesterday "I want the optimization to be turned on at -O1 and
above.”).

— 
Mehdi

> 
> --Sumanth G
> -----Original Message-----
> From: mehdi.amini at apple.com [mailto:mehdi.amini at apple.com] 
> Sent: Friday, January 6, 2017 12:37 PM
> To: Sumanth Gundapaneni <sgundapa at codeaurora.org>
> Cc: jpaquette at apple.com; LLVM Developers <llvm-dev at
lists.llvm.org>
> Subject: Re: [llvm-dev] LLVMTargetMachine with optimization level passed
from clang.
> 
> 
>> On Jan 6, 2017, at 7:59 AM, Sumanth Gundapaneni via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
>> 
>> getOptLevel() gets the level from TargetMachine which is created by 
>> the Backendutil in clang with either "Default",
"None" or "Aggressive". Threre is no correspondence for
"Less".
>> This boils down to , if I pass "-O1", the Target Machine is
created with CodeGenOpt::Default.
> 
> I don’t see why is it a problem? That’s why I asked earlier if you want it
on for O1 *and above* or only O1.
> You just have to enable it when CodeGenOpt is Default or above (or
disabling it when CodeGenOpt::None), or did I miss something?
> 
> —
> Mehdi
> 
> 
>> 
>> I am available on IRC @ sgundapa.
>> 
>> -----Original Message-----
>> From: jpaquette at apple.com [mailto:jpaquette at apple.com] 
>> Sent: Thursday, January 5, 2017 12:24 PM
>> To: sgundapa at codeaurora.org
>> Cc: LLVM Developers <llvm-dev at lists.llvm.org>
>> Subject: Re: [llvm-dev] LLVMTargetMachine with optimization level
passed from clang.
>> 
>> Most of the stuff you’re looking for lives in TargetPassConfig.cpp.
There are a few examples of how you might do it that live in there too.
>> 
>> What it comes down to is finding the place you want your pass to live
and sticking in some logic like this in there:
>> 
>> if (getOptLevel() != CodeGenOpt::None)
>>   addPass(&MyPassID);
>> 
>> A lot of passes are added in just TargetPassConfig::addMachinePasses(),
but some live in more specialized areas like, for the sake of example,
TargetPassConfig::addMachineLateOptimization(). You can add it wherever seems
best for your specific pass.
>> 
>> Hope that helps!
>> 
>> Jessica Paquette
>> 
>>> On Jan 5, 2017, at 8:12 AM, via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
>>> 
>>> I want the optimization to be turned on at -O1 and above.
>>> In my case, it is a target independent back-end pass. (Eg: 
>>> MachinePipeliner)
>>> 
>>> 
>>> On 2017-01-04 18:10, Mehdi Amini wrote:
>>>>> On Jan 4, 2017, at 4:03 PM, Sumanth Gundapaneni via
llvm-dev
>>>>> <llvm-dev at lists.llvm.org> wrote:
>>>>> I see the BackendUtil.cpp of Clang creates the
TargetMachine with
>>>>> the optimization level based on below mentioned logic 
>>>>> CodeGenOpt::Level OptLevel = CodeGenOpt::Default; switch 
>>>>> (CodeGenOpts.OptimizationLevel) {
>>>>> default: break;
>>>>> case 0: OptLevel = CodeGenOpt::None; break; case 3:
OptLevel =
>>>>> CodeGenOpt::Aggressive; break; } As per my understanding,
the
>>>>> correspondence between optimization level and CodeGenOpt is
as below
>>>>> O0  -  none
>>>>> O1  -  less
>>>>> O2 -   default
>>>>> O3  -  aggressive
>>>>> My goal is to turn on a target dependent codegen
optimization at
>>>>> –O1(less).
>>>> Apparently “less” is not used by clang, do you want your
optimization
>>>> to be turned on for O1 *and above* or just for O1 specifically?
>>>> Also what kind of optimization is this? A SelectionDAG combine
or a
>>>> specific pass? If it is a pass, is it IR or MIR?
>>>> —
>>>> Mehdi
>>>>> The TargetMachine is constructed with
“CodeGenOpt::Default”. Is
>>>>> there a way I could do this in LLVM ? What is the standard
way of
>>>>> doing this ? Also, the code in BackendUtil.cpp seem
somewhat offbeat
>>>>> to me.
>>>>> --Sumanth G
>>>>> _______________________________________________
>>>>> LLVM Developers mailing list
>>>>> llvm-dev at lists.llvm.org
>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>> 
>> 
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> 
>

Apologies for the confusion. I was trying to understand why passes were run at
-O1 when they are intended for -O2 and above.
Is there a way I could avoid running optimizations at -O1 that are meant to run
at -O2 and above?

--Sumanth G
-----Original Message-----
From: mehdi.amini at apple.com [mailto:mehdi.amini at apple.com] 
Sent: Friday, January 6, 2017 1:10 PM
To: Sumanth Gundapaneni <sgundapa at codeaurora.org>
Cc: jpaquette at apple.com; LLVM Developers <llvm-dev at lists.llvm.org>
Subject: Re: [llvm-dev] LLVMTargetMachine with optimization level passed from
clang.

> On Jan 6, 2017, at 10:56 AM, Sumanth Gundapaneni <sgundapa at
codeaurora.org> wrote:
> 
> Here is a problem scenario.
> 
> I want to enable a backend pass at -O2 or above.
> if (TM->getOptLevel() >= CodeGenOpt::Default)
>    addPass(&xxxxx);
> 
> This pass will be run at -O1 too since clang is creating the TargetMachine
with CodeGenOpt::Default for -O1.
Right, you can’t.
(You wrote yesterday "I want the optimization to be turned on at -O1 and
above.”).

— 
Mehdi

> 
> --Sumanth G
> -----Original Message-----
> From: mehdi.amini at apple.com [mailto:mehdi.amini at apple.com] 
> Sent: Friday, January 6, 2017 12:37 PM
> To: Sumanth Gundapaneni <sgundapa at codeaurora.org>
> Cc: jpaquette at apple.com; LLVM Developers <llvm-dev at
lists.llvm.org>
> Subject: Re: [llvm-dev] LLVMTargetMachine with optimization level passed
from clang.
> 
> 
>> On Jan 6, 2017, at 7:59 AM, Sumanth Gundapaneni via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
>> 
>> getOptLevel() gets the level from TargetMachine which is created by 
>> the Backendutil in clang with either "Default",
"None" or "Aggressive". Threre is no correspondence for
"Less".
>> This boils down to , if I pass "-O1", the Target Machine is
created with CodeGenOpt::Default.
> 
> I don’t see why is it a problem? That’s why I asked earlier if you want it
on for O1 *and above* or only O1.
> You just have to enable it when CodeGenOpt is Default or above (or
disabling it when CodeGenOpt::None), or did I miss something?
> 
> —
> Mehdi
> 
> 
>> 
>> I am available on IRC @ sgundapa.
>> 
>> -----Original Message-----
>> From: jpaquette at apple.com [mailto:jpaquette at apple.com] 
>> Sent: Thursday, January 5, 2017 12:24 PM
>> To: sgundapa at codeaurora.org
>> Cc: LLVM Developers <llvm-dev at lists.llvm.org>
>> Subject: Re: [llvm-dev] LLVMTargetMachine with optimization level
passed from clang.
>> 
>> Most of the stuff you’re looking for lives in TargetPassConfig.cpp.
There are a few examples of how you might do it that live in there too.
>> 
>> What it comes down to is finding the place you want your pass to live
and sticking in some logic like this in there:
>> 
>> if (getOptLevel() != CodeGenOpt::None)
>>   addPass(&MyPassID);
>> 
>> A lot of passes are added in just TargetPassConfig::addMachinePasses(),
but some live in more specialized areas like, for the sake of example,
TargetPassConfig::addMachineLateOptimization(). You can add it wherever seems
best for your specific pass.
>> 
>> Hope that helps!
>> 
>> Jessica Paquette
>> 
>>> On Jan 5, 2017, at 8:12 AM, via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
>>> 
>>> I want the optimization to be turned on at -O1 and above.
>>> In my case, it is a target independent back-end pass. (Eg: 
>>> MachinePipeliner)
>>> 
>>> 
>>> On 2017-01-04 18:10, Mehdi Amini wrote:
>>>>> On Jan 4, 2017, at 4:03 PM, Sumanth Gundapaneni via
llvm-dev
>>>>> <llvm-dev at lists.llvm.org> wrote:
>>>>> I see the BackendUtil.cpp of Clang creates the
TargetMachine with
>>>>> the optimization level based on below mentioned logic 
>>>>> CodeGenOpt::Level OptLevel = CodeGenOpt::Default; switch 
>>>>> (CodeGenOpts.OptimizationLevel) {
>>>>> default: break;
>>>>> case 0: OptLevel = CodeGenOpt::None; break; case 3:
OptLevel =
>>>>> CodeGenOpt::Aggressive; break; } As per my understanding,
the
>>>>> correspondence between optimization level and CodeGenOpt is
as below
>>>>> O0  -  none
>>>>> O1  -  less
>>>>> O2 -   default
>>>>> O3  -  aggressive
>>>>> My goal is to turn on a target dependent codegen
optimization at
>>>>> –O1(less).
>>>> Apparently “less” is not used by clang, do you want your
optimization
>>>> to be turned on for O1 *and above* or just for O1 specifically?
>>>> Also what kind of optimization is this? A SelectionDAG combine
or a
>>>> specific pass? If it is a pass, is it IR or MIR?
>>>> —
>>>> Mehdi
>>>>> The TargetMachine is constructed with
“CodeGenOpt::Default”. Is
>>>>> there a way I could do this in LLVM ? What is the standard
way of
>>>>> doing this ? Also, the code in BackendUtil.cpp seem
somewhat offbeat
>>>>> to me.
>>>>> --Sumanth G
>>>>> _______________________________________________
>>>>> LLVM Developers mailing list
>>>>> llvm-dev at lists.llvm.org
>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>> _______________________________________________
>>> LLVM Developers mailing list
>>> llvm-dev at lists.llvm.org
>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>> 
>> 
>> _______________________________________________
>> LLVM Developers mailing list
>> llvm-dev at lists.llvm.org
>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> 
>

> -----Original Message-----
> From: llvm-dev [mailto:llvm-dev-bounces at lists.llvm.org] On Behalf Of
Mehdi
> Amini via llvm-dev
> Sent: Friday, January 06, 2017 11:10 AM
> To: Sumanth Gundapaneni
> Cc: LLVM Developers
> Subject: Re: [llvm-dev] LLVMTargetMachine with optimization level passed
> from clang.
> 
> 
> > On Jan 6, 2017, at 10:56 AM, Sumanth Gundapaneni
> <sgundapa at codeaurora.org> wrote:
> >
> > Here is a problem scenario.
> >
> > I want to enable a backend pass at -O2 or above.
> > if (TM->getOptLevel() >= CodeGenOpt::Default)
> >    addPass(&xxxxx);
> >
> > This pass will be run at -O1 too since clang is creating the
> TargetMachine with CodeGenOpt::Default for -O1.
> 
> Right, you can’t.
Can somebody explain why it's not a bug that -O1 and -O2 are identical?
Thanks,
--paulr
> (You wrote yesterday "I want the optimization to be turned on at -O1
and
> above.”).
> 
> —
> Mehdi
> 
> 
> >
> > --Sumanth G
> > -----Original Message-----
> > From: mehdi.amini at apple.com [mailto:mehdi.amini at apple.com]
> > Sent: Friday, January 6, 2017 12:37 PM
> > To: Sumanth Gundapaneni <sgundapa at codeaurora.org>
> > Cc: jpaquette at apple.com; LLVM Developers <llvm-dev at
lists.llvm.org>
> > Subject: Re: [llvm-dev] LLVMTargetMachine with optimization level
passed
> from clang.
> >
> >
> >> On Jan 6, 2017, at 7:59 AM, Sumanth Gundapaneni via llvm-dev
<llvm-
> dev at lists.llvm.org> wrote:
> >>
> >> getOptLevel() gets the level from TargetMachine which is created
by
> >> the Backendutil in clang with either "Default",
"None" or "Aggressive".
> Threre is no correspondence for "Less".
> >> This boils down to , if I pass "-O1", the Target Machine
is created
> with CodeGenOpt::Default.
> >
> > I don’t see why is it a problem? That’s why I asked earlier if you
want
> it on for O1 *and above* or only O1.
> > You just have to enable it when CodeGenOpt is Default or above (or
> disabling it when CodeGenOpt::None), or did I miss something?
> >
> > —
> > Mehdi
> >
> >
> >>
> >> I am available on IRC @ sgundapa.
> >>
> >> -----Original Message-----
> >> From: jpaquette at apple.com [mailto:jpaquette at apple.com]
> >> Sent: Thursday, January 5, 2017 12:24 PM
> >> To: sgundapa at codeaurora.org
> >> Cc: LLVM Developers <llvm-dev at lists.llvm.org>
> >> Subject: Re: [llvm-dev] LLVMTargetMachine with optimization level
> passed from clang.
> >>
> >> Most of the stuff you’re looking for lives in
TargetPassConfig.cpp.
> There are a few examples of how you might do it that live in there too.
> >>
> >> What it comes down to is finding the place you want your pass to
live
> and sticking in some logic like this in there:
> >>
> >> if (getOptLevel() != CodeGenOpt::None)
> >>   addPass(&MyPassID);
> >>
> >> A lot of passes are added in just
TargetPassConfig::addMachinePasses(),
> but some live in more specialized areas like, for the sake of example,
> TargetPassConfig::addMachineLateOptimization(). You can add it wherever
> seems best for your specific pass.
> >>
> >> Hope that helps!
> >>
> >> Jessica Paquette
> >>
> >>> On Jan 5, 2017, at 8:12 AM, via llvm-dev <llvm-dev at
lists.llvm.org>
> wrote:
> >>>
> >>> I want the optimization to be turned on at -O1 and above.
> >>> In my case, it is a target independent back-end pass. (Eg:
> >>> MachinePipeliner)
> >>>
> >>>
> >>> On 2017-01-04 18:10, Mehdi Amini wrote:
> >>>>> On Jan 4, 2017, at 4:03 PM, Sumanth Gundapaneni via
llvm-dev
> >>>>> <llvm-dev at lists.llvm.org> wrote:
> >>>>> I see the BackendUtil.cpp of Clang creates the
TargetMachine with
> >>>>> the optimization level based on below mentioned logic
> >>>>> CodeGenOpt::Level OptLevel = CodeGenOpt::Default;
switch
> >>>>> (CodeGenOpts.OptimizationLevel) {
> >>>>> default: break;
> >>>>> case 0: OptLevel = CodeGenOpt::None; break; case 3:
OptLevel > >>>>> CodeGenOpt::Aggressive; break; } As per my
understanding, the
> >>>>> correspondence between optimization level and
CodeGenOpt is as below
> >>>>> O0  -  none
> >>>>> O1  -  less
> >>>>> O2 -   default
> >>>>> O3  -  aggressive
> >>>>> My goal is to turn on a target dependent codegen
optimization at
> >>>>> –O1(less).
> >>>> Apparently “less” is not used by clang, do you want your
optimization
> >>>> to be turned on for O1 *and above* or just for O1
specifically?
> >>>> Also what kind of optimization is this? A SelectionDAG
combine or a
> >>>> specific pass? If it is a pass, is it IR or MIR?
> >>>> —
> >>>> Mehdi
> >>>>> The TargetMachine is constructed with
“CodeGenOpt::Default”. Is
> >>>>> there a way I could do this in LLVM ? What is the
standard way of
> >>>>> doing this ? Also, the code in BackendUtil.cpp seem
somewhat offbeat
> >>>>> to me.
> >>>>> --Sumanth G
> >>>>> _______________________________________________
> >>>>> LLVM Developers mailing list
> >>>>> llvm-dev at lists.llvm.org
> >>>>>
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> >>> _______________________________________________
> >>> LLVM Developers mailing list
> >>> llvm-dev at lists.llvm.org
> >>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> >>
> >>
> >> _______________________________________________
> >> LLVM Developers mailing list
> >> llvm-dev at lists.llvm.org
> >> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
> >
> >
> 
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev