search for: prepasses

hi, i`m working on a machine instruction scheduler for an VLIW architecture. loads are somewhat expensive on this architecture, thus i would like to reorder unrelated loads/stores to better hide load latencies. to do this, i would need alias information on machine instructions, i.e., which machine instructions may access the same memory region. as far as i know, this is not available at the

On Mon, 30 Apr 2007, Florian Brandner wrote: > i`m working on a machine instruction scheduler for an VLIW architecture. > loads are somewhat expensive on this architecture, thus i would like to > reorder unrelated loads/stores to better hide load latencies. > > to do this, i would need alias information on machine instructions, > i.e., which machine instructions may access the

Chris Lattner wrote: > There are a couple of ways to do this. Is your scheduler a prepass > scheduler (before regalloc) or a post-pass scheduler (after regalloc)? it is a post-pass scheduler, which operates on MachineInstrs. we need to run it after register allocation to hide latencies of spill code, prolog, and epilog. > If you want to extract maximal parallelism, I assume you want a

>On Aug 16, 2012, at 1:09 PM, "Rao, Prashantha" <Prashantha.Rao at amd.com<mailto:Prashantha.Rao at amd.com>> wrote: >Hi- >I am writing a pass to traverse loops and collect some analysis data and later on come back to transform the IR. In the analysis phase I need to >remember statistics regarding every loop in the program. What is the best way to uniquely

From: Andrew Trick [mailto:atrick at apple.com] Sent: Tuesday, August 21, 2012 9:58 PM To: Rao, Prashantha Cc: llvmdev at cs.uiuc.edu Subject: Re: [LLVMdev] How to uniquely remember a loop? On Aug 21, 2012, at 4:17 AM, "Rao, Prashantha" <Prashantha.Rao at amd.com<mailto:Prashantha.Rao at amd.com>> wrote: More than one loop may share the same header; You have a different

On Aug 21, 2012, at 4:17 AM, "Rao, Prashantha" <Prashantha.Rao at amd.com> wrote: > More than one loop may share the same header; You have a different definition of loop than the rest of the optimizer. You can identify your loops by the backedge if you prefer. > I can certainly run LoopSimplify as a prepass. But will that ensure unique loop header for each loop. It tries

On Fri, 4 May 2007, Florian Brandner wrote: > Chris Lattner wrote: >> There are a couple of ways to do this. Is your scheduler a prepass >> scheduler (before regalloc) or a post-pass scheduler (after regalloc)? > > it is a post-pass scheduler, which operates on MachineInstrs. we need to > run it after register allocation to hide latencies of spill code, > prolog, and

...correct way to reproduce llvm-gcc -O3 output with the opt tool? It's a bit complicated, because llvm-gcc runs a couple of local passes as it parses and builds the llvm code, then it runs the passes above on the whole module afterwards. I don't know if there is a good way to get the prepasses, Devang, do you know? -Chris

Hi, Recently, I was looking into the bug #1227. I wanted to check if reordering optimization passes could solve it. To start with, I tried to reproduce the output of llvm-g++ -O3 using the combination of llvm-g++ -O0 and opt with the appropriate passes. However, I was unable to. I use SVN versions of llvm and llvm-gcc-4.2. First, I compile example.cpp (attached; taken from the bug #1227) with: $

On 01/13/10 00:56, Jan Sjodin wrote: > Why not use the "standard" algorithm for detecting SESE-regions and building a program structure tree? > It should handle everything you want. It also becomes much simpler to specify a connected SESE-region > by entry/exit edges, while a disconnected region is specified by entry/exit blocks. Only defining regions on > blocks is not

...ork with these instructions 1. Not the right preoptimization passes The instructions on the Polly website use a very short sequence of preoptimization passes that just matches the simple example presented. To optimize real world programs that are not 100% standard you need a larger sequence of prepasses. In your example the loop iv does not start at '0' so further canonicalication is required. The minimal sequence of optimization passes for your example is: opt -mem2reg -instcombine -simplifycfg -loop-rotate -indvars 2. -enable-iv-rewrite LLVM recently disabled by default the induction...

...d/store instructions into scalar operations. Is it possible to run such a pass before polly-dependence analysis? Star Tan At 2013-08-15 21:12:53,"Sebastian Pop" <sebpop at gmail.com> wrote: >Codeprepare and independent blocks are introducing these loads and stores. >These are prepasses that polly runs prior to building the dependence graph >to transform scalar dependences into data dependences. >Ether was working on eliminating the rewrite of scalar dependences. > >On Thu, Aug 15, 2013 at 5:32 AM, Star Tan <tanmx_star at yeah.net> wrote: >> Hi all, >&gt...

Hi- I am writing a pass to traverse loops and collect some analysis data and later on come back to transform the IR. In the analysis phase I need to remember statistics regarding every loop in the program. What is the best way to uniquely remember a loop? Thanks, -Prashantha -------------- next part -------------- An HTML attachment was scrubbed... URL:

On Aug 16, 2012, at 1:09 PM, "Rao, Prashantha" <Prashantha.Rao at amd.com> wrote: > Hi- > > I am writing a pass to traverse loops and collect some analysis data and later on come back to transform the IR. In the analysis phase I need to remember statistics regarding every loop in the program. What is the best way to uniquely remember a loop? Probably too late to help

Hi Kaarl, > I work with APC SmartUPS which we use for the PrePass (Truck signaling and weigh station bypass system) system in > order to power our remote cabinets. We can access our SmartUPS 420s (mostly) from a UnixWare 2 computer that > has Ethernet communications to a serial comm server (Iolan) using a "cu" command: > cu i_ups. That gets me to the command line of

Codeprepare and independent blocks are introducing these loads and stores. These are prepasses that polly runs prior to building the dependence graph to transform scalar dependences into data dependences. Ether was working on eliminating the rewrite of scalar dependences. On Thu, Aug 15, 2013 at 5:32 AM, Star Tan <tanmx_star at yeah.net> wrote: > Hi all, > > I have investigat...

I add also the output of these commands: [hades at artemis examples]$ ./compile_ex.sh super_simple_loop Printing analysis 'Polly - Detect Scops in functions' for function 'main': [hades at artemis examples]$ modifying it in : #include <stdio.h> int main() { int A[1024]; int j, k=10; for (j = 0; j < 1024; j++) A[j] = k;

...operations. Is it possible to run such > a pass before polly-dependence analysis? > > Star Tan > > At 2013-08-15 21:12:53,"Sebastian Pop" <sebpop at gmail.com> wrote: >>Codeprepare and independent blocks are introducing these loads and stores. >>These are prepasses that polly runs prior to building the dependence graph >>to transform scalar dependences into data dependences. >>Ether was working on eliminating the rewrite of scalar dependences. >> >>On Thu, Aug 15, 2013 at 5:32 AM, Star Tan <tanmx_star at yeah.net> wrote: >>...

On 01/13/10 05:09, Jan Sjodin wrote: > Hi Tobias > >> In general this approach saves a preliminary pass that has to insert new > >> bbs, to generate these edges. As we do not have to modify the CFG other >> passes like dominance information are still valid, and we do not have to >> create a lot of auxiliary bbs, to be able to detect all regions. This >>

Hi Tobias, thanks for the answer. I'll try to give a look to the code you pointed me to , and I'll try to make the modification myself. I'm new to LLVM and Polly, but the code of both seem clean and understandable, so I hope to be able to do it myself. In case I'll ask here for support :) Marcello 2011/10/1 Tobias Grosser <tobias at grosser.es>: > On 10/01/2011 03:26