llvm dev - Dec 2016 - Dumping compiled module as LLVM IR bitcode after certain optimization passes

Hello.
     Is there a possibility to instruct at command line the clang or the opt
tools to emit
LLVM bitcode file after a certain optimization pass such as LoopVectorize (or
all
optimization passes)? (This question was asked also at 
http://stackoverflow.com/questions/17904440/dump-ir-after-each-llvm-optimization-each-pass-both-llvm-ir-passes-and-backen
.)
     As far as I can see giving:
       clang -save-temps ...
     generates a .bc file for the compiled module just before passing the module
to the
optimization passes (opt).

     An alternative I have is to programmatically generate the corresponding
bitcode file
at the right time after finishing the pass in discussion - see, for example, 
http://stackoverflow.com/questions/13903686/writing-module-to-bc-bitcode-file,
methods
WriteBitcodeToFile() or WriteModule() .

   Thank you,
     Alex

Hi,

Usually we disable the llvm optimizations (clang -mllvm disable-llvm-optzns )
and then use opt to run the passes till the point of interest. I don’t know of a
shortcut in clang (the new PassManager will make it possible to pass an
arbitrary pipeline with a string, but not there yet).

— 
Mehdi
> On Dec 31, 2016, at 11:43 AM, Alex Susu via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
> 
>  Hello.
>    Is there a possibility to instruct at command line the clang or the opt
tools to emit LLVM bitcode file after a certain optimization pass such as
LoopVectorize (or all optimization passes)? (This question was asked also at
http://stackoverflow.com/questions/17904440/dump-ir-after-each-llvm-optimization-each-pass-both-llvm-ir-passes-and-backen
.)
>    As far as I can see giving:
>      clang -save-temps ...
>    generates a .bc file for the compiled module just before passing the
module to the optimization passes (opt).
> 
>    An alternative I have is to programmatically generate the corresponding
bitcode file at the right time after finishing the pass in discussion - see, for
example,
http://stackoverflow.com/questions/13903686/writing-module-to-bc-bitcode-file,
methods WriteBitcodeToFile() or WriteModule() .
> 
>  Thank you,
>    Alex
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev

Also, if I have a small test-case, using `clang -mllvm -print-after-all` is
convenient to get the IR at any point.
Adding "-filter-print-funcs” can help reducing the amount in the output to
a single function (or a list of functions), for example:
`clang  -mllvm -filter-print-funcs=_Z3foov -mllvm -print-after-all`.

(There is a print-after option but it does not work in clang).

— 
Mehdi



> On Dec 31, 2016, at 12:09 PM, Mehdi Amini via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
> 
> Hi,
> 
> Usually we disable the llvm optimizations (clang -mllvm disable-llvm-optzns
) and then use opt to run the passes till the point of interest. I don’t know of
a shortcut in clang (the new PassManager will make it possible to pass an
arbitrary pipeline with a string, but not there yet).
> 
> — 
> Mehdi
> 
>> On Dec 31, 2016, at 11:43 AM, Alex Susu via llvm-dev <llvm-dev at
lists.llvm.org> wrote:
>> 
>> Hello.
>>   Is there a possibility to instruct at command line the clang or the
opt tools to emit LLVM bitcode file after a certain optimization pass such as
LoopVectorize (or all optimization passes)? (This question was asked also at
http://stackoverflow.com/questions/17904440/dump-ir-after-each-llvm-optimization-each-pass-both-llvm-ir-passes-and-backen
.)
>>   As far as I can see giving:
>>     clang -save-temps ...
>>   generates a .bc file for the compiled module just before passing the
module to the optimization passes (opt).
>> 
>>   An alternative I have is to programmatically generate the
corresponding bitcode file at the right time after finishing the pass in
discussion - see, for example,
http://stackoverflow.com/questions/13903686/writing-module-to-bc-bitcode-file,
methods WriteBitcodeToFile() or WriteModule() .
>> 
>> Thank you,
>>   Alex
>> _______________________________________________
>> 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