similar to: [LLVMdev] Loop Unroll a constant number of times?

On Jan 31, 2012, at 5:16 PM, Ryan Taylor <ryta1203 at gmail.com> wrote: > Is it possible to unroll a loop (forcibly if necessary) with llvm (possibly the -loop-unroll pass) a constant number of times. > > I believe that I read that the -unroll-count=x option was removed, correct? So is there some other way to do this or is this just not possible in llvm? See clang -mllvm

hi, In "LoopUnrollPass.cpp", when trying to reduce unroll count to meet the unroll threshold requirement in line 200 and line 206, variable "CurrentThreshold" is used in the computation, instead of the variable "Threshold", which is defined by: // Determine the current unrolling threshold. While this is normally set // from UnrollThreshold, it is overridden to

I am trying loop-unroll optimization but it is not affecting the bit code. When I looked the loop unroll code it seems to be expecting three parameter(UnrollThreshold, UnrollCount, UnrollAllowPartial) from the user. Do I need to pass these parameter to activate loop unroll? *The loop that I am trying it on is:* for(i=0; i< 1000; i++) { c[i] = a[i] + b[i]; } -------------- next

In r200270 I added support to unroll conditional stores in the loop vectorizer. It is currently off pending further benchmarking and can be enabled with "-mllvm -vectorize-num-stores-pred=1”. Furthermore, I added a heuristic to unroll until load/store ports are saturated “-mllvm enable-loadstore-runtime-unroll” instead of the pure size based heuristic. Those two together with a patch that

Hi all, I meet this problem when compiling the TREAM benchmark ( http://www.cs.virginia.edu/stream/FTP/Code/) with enable-misched The small function will be scheduled as good code, but if opt inline this function, the inline part will be scheduled as bad code. so I rewrite a simple code as attached link (foo.c), and compiled with two different methods: *method A:* *$clang -O3 foo.c -static -S

On Tue, 2011-11-08 at 12:12 +0100, Tobias Grosser wrote: > On 11/08/2011 11:45 AM, Hal Finkel wrote: > > I've attached the latest version of my autovectorization patch. > > > > Working through the test suite has proved to be a productive > > experience ;) -- And almost all of the bugs that it revealed have now > > been fixed. There are still two programs that

We've notice that when loops are unrolled there seems to be a limit of 64 subexpressions that can be assigned to registers. In our architecture we've got a lot more registers available than just 64. Is there some parameter we can change to the loop unroller that allows more subexpressions to be assigned to a number of registers beyond 64? Phil -------------- next part -------------- An

On 11/08/2011 03:36 PM, Hal Finkel wrote: > On Tue, 2011-11-08 at 12:12 +0100, Tobias Grosser wrote: >> On 11/08/2011 11:45 AM, Hal Finkel wrote: >>> I've attached the latest version of my autovectorization patch. >>> >>> Working through the test suite has proved to be a productive >>> experience ;) -- And almost all of the bugs that it revealed

On Oct 14, 2013, at 3:27 AM, Zakk <zakk0610 at gmail.com> wrote: > Hi all, > I meet this problem when compiling the TREAM benchmark (http://www.cs.virginia.edu/stream/FTP/Code/) with enable-misched > > The small function will be scheduled as good code, but if opt inline this function, the inline part will be scheduled as bad code. A bug for this is welcome. Pretty soon, I’ll

As some of you may know, I committed my basic-block autovectorization pass a few days ago. I encourage anyone interested to try it out (pass -vectorize to opt or -mllvm -vectorize to clang) and provide feedback. Especially in combination with -unroll-allow-partial, I have observed some significant benchmark speedups, but, I have also observed some significant slowdowns. I would like to share my

Yes that is what he meant. "-dce, -adce, etc" are command line options consumed by tools/opt/opt.cpp to give to the PassManagerBuilder that it creates. The parsing of those options doesn't exist in any of the llvm library code that is linked into clang. Clang has its own code for populating a PassManagerBuilder in tools/clang/lib/CodeGen/BackendUtil.cpp ~Craig On Mon, Jan 8, 2018

Thanks, Craig. So, clang -Xclang -disable-llvm-passes actually disables all the LLVM passed populated by clang so that there is no middle-end optimization on bc files. clang -O2 LULESH.c //clang is the driver, invoking cc1, cc1as, ld //options can be passed through to cc1 directly. //maybe have different names, e.g.

Hi Andy, thanks for your help!! The scheduled code by method A is same as B when using the new machine model. it's make sense, but there is the another problem, the scheduled code is badly. load/store instruction always reuse the same register Source: #define N 2000000 static double b[N], c[N]; void Scale () { double scalar = 3.0; for (int j=0;j<N;j++) b[j] =

I want to control the unroll factor using the command line flag “-force-vector-unroll”, such as "clang -mllvm -force-vector-unroll=2", but produce an error: " clang-4.0: error: unknown argument: '-force-vector-unroll=2' " . could you help me ？

//mllvm Options can be dumped by clang -v -help -mllvm and clang -v --help-hidden --> //mllvm Options can be dumped by clang -v -help -mllvm and clang -v --help-hidden -mllvm On Tue, Jan 9, 2018 at 3:09 AM, toddy wang <wenwangtoddy at gmail.com> wrote: > Thanks, Craig. > > So, clang -Xclang -disable-llvm-passes actually disables all the LLVM > passed populated by clang so

On Sun, 24 Jun 2012 14:44:45 +0200 Tobias Grosser <tobias at grosser.es> wrote: > On 06/24/2012 02:42 PM, Hal Finkel wrote: > > On Sun, 24 Jun 2012 08:17:32 +0200 > > Tobias Grosser<tobias at grosser.es> wrote: > > > >> On 06/24/2012 05:42 AM, Hal Finkel wrote: > >>> On Thu, 21 Jun 2012 16:25:13 +0200 > >>> Tobias

Carl-Philip, The reason that this does not vectorize is that it cannot vectorize the stores; this leaves only the mul-add chains (and some chains with loads), and they only have a depth of 2 (the threshold is 6). If you give clang -mllvm -bb-vectorize-req-chain-depth=2 then it will vectorize. The reason the heuristic has such a large default value is to prevent cases where it costs more to

Hi everybody, I'm trying to run some examples with different backend options (turning on/off SSE, 3dnow, or MMX instructions). However, I don't see any difference in terms of execution time. Does anybody know which language constructs (in C/C++ preferably) should I try to make these instructions generated (and thus make a difference between a backend that enables them or not) ? I tried

How can I install the patch? Any step-by-step guide? Thanks, Pablo On 24/11/2011, at 15:33, Hal Finkel wrote: > On Thu, 2011-11-24 at 15:09 +0100, Pablo Barrio López-Cortijo wrote: >> Hi everybody, >> >> I'm trying to run some examples with different backend options (turning >> on/off SSE, 3dnow, or MMX instructions). However, I don't see any >>

On 16/01/2014, 23:47 , Andrew Trick wrote: > > On Jan 15, 2014, at 4:13 PM, Diego Novillo <dnovillo at google.com > <mailto:dnovillo at google.com>> wrote: > >> Chandler also pointed me at the vectorizer, which has its own >> unroller. However, the vectorizer only unrolls enough to serve the >> target, it's not as general as the runtime-triggered