Re: CMM-to-ASM: Register allocation wierdness

Harendra Kumar writes: > On 19 June 2016 at 14:03, Ben Gamari wrote: > >> >> Indeed it would be great if you could provide the program that produced >> this code. >> >> >> It would be great to open Trac tickets to track some of the optimization >

Re: CMM-to-ASM: Register allocation wierdness

On 19 June 2016 at 14:03, Ben Gamari wrote: > > Indeed it would be great if you could provide the program that produced > this code. > > >> It would be great to open Trac tickets to track some of the optimization Ok, I created an account on ghc trac and raised two

Re: CMM-to-ASM: Register allocation wierdness

Harendra Kumar writes: > Thanks Ben! I have my responses inline below. > No worries! > On 16 June 2016 at 18:07, Ben Gamari wrote: > >> For the record, I have also struggled with register spilling issues in >> the past. See, for instance,

Re: CMM-to-ASM: Register allocation wierdness

On Sun, Jun 19, 2016 at 12:30 AM, Carter Schonwald < carter.schonw...@gmail.com> wrote: > This email would have been marked spam had I not unmarked all your emails > as spam. Also a gmail user :/ Same. I forwarded my received headers to the infra folks; they made some more adjustments to

Re: CMM-to-ASM: Register allocation wierdness

> > > > > *From:* Takenobu Tani [mailto:takenobu...@gmail.com > <javascript:_e(%7B%7D,'cvml','takenobu...@gmail.com');>] > *Sent:* 18 June 2016 08:18 > *To:* Simon Peyton Jones <simo...@microsoft.com > <javascript:_e(%7B%7D,'cvml','simo...@microsoft.com');>>

Re: CMM-to-ASM: Register allocation wierdness

gt; Simon > > > > > *From:* Takenobu Tani [mailto:takenobu...@gmail.com] > *Sent:* 18 June 2016 08:18 > *To:* Simon Peyton Jones <simo...@microsoft.com> > *Subject:* Re: CMM-to-ASM: Register allocation wierdness > > > > Hi Simon, > > > > I report to you a

RE: CMM-to-ASM: Register allocation wierdness

, could you let me know? Thanks Simon From: Takenobu Tani [mailto:takenobu...@gmail.com] Sent: 18 June 2016 08:18 To: Simon Peyton Jones <simo...@microsoft.com> Subject: Re: CMM-to-ASM: Register allocation wierdness Hi Simon, I report to you about your mails. Maybe, your mails don't reach to

Re: CMM-to-ASM: Register allocation wierdness

Thanks Ben! I have my responses inline below. On 16 June 2016 at 18:07, Ben Gamari wrote: > > Indeed; I've opened D2335 [1] to reenable -fregs-graph and add an > appropriate note to the users guide. > Thanks! That was quick. > For the record, I have also struggled with

Re: CMM-to-ASM: Register allocation wierdness

Ccing David Spitzenberg, who has thought about proc-point splitting, which is relevant for reasons that we will see below. Harendra Kumar writes: > On 16 June 2016 at 13:59, Ben Gamari wrote: >> >> It actually came to my attention while

RE: CMM-to-ASM: Register allocation wierdness

| All-in-all, the graph coloring allocator is in great need of some love; | Harendra, perhaps you'd like to have a try at dusting it off and perhaps | look into why it regresses in compiler performance? It would be great if | we could use it by default. I second this. Volunteers are sorely

Re: CMM-to-ASM: Register allocation wierdness

That's a nice read, thanks for the pointer. I agree with the solution presented there. If we can do that it will be awesome. If help is needed I can spend some time on it. One of the things that I noticed is that the code can be optimized significantly if we know the common case so that we can

Re: CMM-to-ASM: Register allocation wierdness

On 06/16/16 12:53 PM, Harendra Kumar wrote: A thought that came to my mind was whether we should focus on getting better code out of the llvm backend or the native code generator. LLVM seems pretty good at the specialized task of code generation and low level optimization, it is well funded,

Re: CMM-to-ASM: Register allocation wierdness

On 16 June 2016 at 13:59, Ben Gamari wrote: > > It actually came to my attention while researching this that the > -fregs-graph flag is currently silently ignored [2]. Unfortunately this > means you'll need to build a new compiler if you want to try using it. Yes I did try

Re: CMM-to-ASM: Register allocation wierdness

Harendra Kumar writes: > My earlier experiment was on GHC-7.10.3. I repeated this on GHC-8.0.1 and > the assembly traced was exactly the same except for a marginal improvement. > The 8.0.1 code generator removed the r14/r11 swap but the rest of the > register ring shift

Re: CMM-to-ASM: Register allocation wierdness

> Hi, I am implementing unicode normalization in Haskell. I > challenged myself to match the performance with the best C/C++ > implementation, the best being the ICU library. I am almost there, > beating it in one of the benchmarks and within 30% for others. I am > out of all application level

Re: CMM-to-ASM: Register allocation wierdness

My earlier experiment was on GHC-7.10.3. I repeated this on GHC-8.0.1 and the assembly traced was exactly the same except for a marginal improvement. The 8.0.1 code generator removed the r14/r11 swap but the rest of the register ring shift remains the same. I have updated the github gist with the