How to disable few passes from O1 optimization

Beginners
,
1

Hi All ,

I want to disable fe passes from O1 optimization . How can I implement in the source code . In which file I need to modify to skip few pass to invoke .

If there is any way from command line or source code . If anyone can help me

2

The pass pipeline is defined in this file: llvm-project/PassBuilderPipelines.cpp at main · llvm/llvm-project · GitHub

You should be able to adjust the passes that run by modifying this file.

3

If I comment out the few passes here then how could I understand whether they have any dependencies or not .

Also how will I test that commented passes are not running .

Thanks

On Wed, May 24, 2023, 2:12 PM Florian Hahn via LLVM Discussion Forums <notifications@llvm.discoursemail.com> wrote:

fhahn
May 24

The pass pipeline is defined in this file: llvm-project/PassBuilderPipelines.cpp at main · llvm/llvm-project · GitHub

You should be able to adjust the passes that run by modifying this file.

Visit Topic or reply to this email to respond.

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4

It depends on what kind of dependencies you’re asking here. LLVM’s analyses are calculated on-demand so you don’t have to worry about such dependency. If you’re asking dependencies on some canonicalization Passes (e.g. LoopSimplify), to my best understanding, I don’t think we express those kind of dependencies explicitly.

If you’re using opt (with new PassManager) then -debug-pass-manager will list all the Passes in the pipeline; for llc it’s -debug-pass=Structure.

5

Thanks for your response .

I will try that .

On Wed, May 24, 2023 at 4:06 PM Min-Yih Hsu via LLVM Discussion Forums <notifications@llvm.discoursemail.com> wrote:

mshockwave
May 24

soma_p:

If I comment out the few passes here then how could I understand whether they have any dependencies or not .

It depends on what kind of dependencies you’re asking here. LLVM’s analyses are calculated on-demand so you don’t have to worry about such dependency. If you’re asking dependencies on some canonicalization Passes (e.g. LoopSimplify), to my best understanding, I don’t think we express those kind of dependencies explicitly.

soma_p:

Also how will I test that commented passes are not running .

If you’re using opt (with new PassManager) then -debug-pass-manager will list all the Passes in the pipeline; for llc it’s -debug-pass=Structure.

Visit Topic or reply to this email to respond.

To unsubscribe from these emails, click here.

6

Hi ,

I figured out a file in which some passes are disabled: llvm/lib/CodeGen/TargetPassConfig.cpp
Here few backend passes are disabled and enabled but I am getting the implementation logic. Can I add a few more passes here to disable .

If anyone can help me to understand .

Thanks

On Wed, May 24, 2023 at 4:54 PM soma pal <soma.pal1@gmail.com> wrote:

Thanks for your response .

I will try that .

On Wed, May 24, 2023 at 4:06 PM Min-Yih Hsu via LLVM Discussion Forums <notifications@llvm.discoursemail.com> wrote:

mshockwave
May 24

soma_p:

If I comment out the few passes here then how could I understand whether they have any dependencies or not .

It depends on what kind of dependencies you’re asking here. LLVM’s analyses are calculated on-demand so you don’t have to worry about such dependency. If you’re asking dependencies on some canonicalization Passes (e.g. LoopSimplify), to my best understanding, I don’t think we express those kind of dependencies explicitly.

soma_p:

Also how will I test that commented passes are not running .

If you’re using opt (with new PassManager) then -debug-pass-manager will list all the Passes in the pipeline; for llc it’s -debug-pass=Structure.

Visit Topic or reply to this email to respond.

To unsubscribe from these emails, click here.

7

Could you please help how could I run using Clang . As I am working on optimization , so I need to disable specific passes using clang not opt