• Stefan Koch (12/12) Dec 13 2016 Hi Guys,
• Stefan Koch (4/16) Dec 13 2016 https://github.com/UplinkCoder/dmd/compare/newCTFE...newCTFE-PGO
• Era Scarecrow (3/10) Dec 13 2016 Aside from just counting the results, is this going to possibly
• Stefan Koch (8/11) Dec 14 2016 Well Yes.

Stefan Koch <uplink.coder googlemail.com> writes:

Hi Guys,

Implementing and TESTING function-call support is boring so ...

I have just written a little piece of code that counts which 
switch-cases are executed most frequently versus how often their 
conditions are evaluated.

This can essentially be the basis for pgo based on the 
ctfe-function path.
Since functions are supposed to be the same at ctfe and at 
runtime, you basically get profiling information for free while 
compiling.

Cheers,
Stefan

Stefan Koch <uplink.coder googlemail.com> writes:

On Wednesday, 14 December 2016 at 05:07:17 UTC, Stefan Koch wrote:
 Hi Guys,

 Implementing and TESTING function-call support is boring so ...

 I have just written a little piece of code that counts which 
 switch-cases are executed most frequently versus how often 
 their conditions are evaluated.

 This can essentially be the basis for pgo based on the 
 ctfe-function path.
 Since functions are supposed to be the same at ctfe and at 
 runtime, you basically get profiling information for free while 
 compiling.

 Cheers,
 Stefan

https://github.com/UplinkCoder/dmd/compare/newCTFE...newCTFE-PGO
This is the code that was necessary to add execution counters.
I'd say it does speak for the soundness of the design :)

Era Scarecrow <rtcvb32 yahoo.com> writes:

On Wednesday, 14 December 2016 at 05:07:17 UTC, Stefan Koch wrote:
 I have just written a little piece of code that counts which 
 switch-cases are executed most frequently versus how often 
 their conditions are evaluated.

 This can essentially be the basis for pgo based on the 
 ctfe-function path. Since functions are supposed to be the same 
 at ctfe and at runtime, you basically get profiling information 
 for free while compiling.

  Aside from just counting the results, is this going to possibly 
affect compilation/code generation to get speed/size optimization?

Stefan Koch <uplink.coder googlemail.com> writes:

On Wednesday, 14 December 2016 at 06:00:08 UTC, Era Scarecrow 
wrote:

  Aside from just counting the results, is this going to 
 possibly affect compilation/code generation to get speed/size 
 optimization?

Well Yes.
That is the plan at least :)
CTFE could stream it's branch-counts directly into the optimizer.

I am not in the position to say how tricky it would be to provide 
this information to the backend, but I guess it will take a bit 
of fiddling.