similar to: Instruction selection algorithm

Hi Ivan, Matcher table generation which is implemented in utils/DAGISelEmitter.cpp does use heusiristics like number of instructions which a pattern will cover, latency (not the one which Targets scheduling defines) while emitting the candidate patterns for a give dag node. Current implications may not be implication of algorithm in toto though. Thanks, Jatin On Wednesday, March 28, 2018, Ivan

LLVM performs a greedy, bottom-up instruction selection. At each step, it selects the pattern that will absorb the most nodes (roughly: the order can be tweaked by the target using AddedComplexity, which is often used to model the idea that a particular pattern is more profitable than it would otherwise appear). I don’t personally think there is that much to gain from an algorithm significantly

Hi, I'm new to LLVM and I'm doing research on factors of compilation time, especially instruction selection and scheduling. One of the academic papers I read, https://llvm.org/svn/llvm-project/www-pubs/trunk/2008-CGO-DagISel.pdf (Koes, David Ryan, and Seth Copen Goldstein. "Near-optimal instruction selection on dags."), which is also said to be the algorithm LLVM currently

Thanks for swift reply > Ahmed Bougacha <ahmed.bougacha at gmail.com> 於 2016年6月28日 下午8:11 寫道： > > On Tue, Jun 28, 2016 at 4:42 AM, Bekket McClane via llvm-dev > <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote: >> Hi, >> I'm new to LLVM and I'm doing research on factors of compilation time, >> especially instruction

On Tue, Jun 28, 2016 at 4:42 AM, Bekket McClane via llvm-dev <llvm-dev at lists.llvm.org> wrote: > Hi, > I'm new to LLVM and I'm doing research on factors of compilation time, > especially instruction selection and scheduling. One of the academic papers > I read, > https://llvm.org/svn/llvm-project/www-pubs/trunk/2008-CGO-DagISel.pdf (Koes, > David Ryan, and Seth

I have a few questions about matching in the selector. 1. Why does the size of the MatcherTable greatly exceed the number of patterns defined in the target description? If it simply contains all the variants of the patterns then what is the encoding of these entries ? 2. Is there a simple way to extract the root opcode of a pattern from the MatcherTable entry ? 3. I believe the entries in the

On Tue, Jun 28, 2016 at 5:49 AM, Bekket McClane <bekket.mcclane at gmail.com> wrote: > Thanks for swift reply > > Ahmed Bougacha <ahmed.bougacha at gmail.com> 於 2016年6月28日 下午8:11 寫道： > > On Tue, Jun 28, 2016 at 4:42 AM, Bekket McClane via llvm-dev > <llvm-dev at lists.llvm.org> wrote: > > Hi, > I'm new to LLVM and I'm doing research on factors

> Mehdi Amini <mehdi.amini at apple.com> 於 2016年11月30日 上午5:14 寫道： > >> >> On Nov 29, 2016, at 4:02 AM, Bekket McClane via llvm-dev <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote: >> >> Hi, >> Though there exists lots of researches on parallelizing or scheduling optimization passes, If you open up the time matrices of

Hi, Though there exists lots of researches on parallelizing or scheduling optimization passes, If you open up the time matrices of codegen(llc -time-passes), you'll find that the most time consuming task is actually instruction selection(40~50% of time) instead of optimization passes(10~0%). That's why we're trying to parallelize the (target-independent) instruction selection process

> On Nov 29, 2016, at 1:14 PM, Mehdi Amini <mehdi.amini at apple.com> wrote: > > >> On Nov 29, 2016, at 4:02 AM, Bekket McClane via llvm-dev <llvm-dev at lists.llvm.org <mailto:llvm-dev at lists.llvm.org>> wrote: >> >> Hi, >> Though there exists lots of researches on parallelizing or scheduling optimization passes, If you open up the time

Hello. Are you aware of any document (preferably academic paper) describing TableGen's typing of the following fields used to describe Instruction: pattern, ins and outs. I found a few pages on TableGen, but none of them talking about these fields: http://llvm.org/docs/TableGen/LangRef.html http://llvm.org/docs/TableGen/LangIntro.html

On Tue, Jun 3, 2014 at 7:30 AM, Renato Golin <renato.golin at linaro.org> wrote: > On 3 June 2014 14:10, Daniil Troshkov <troshkovdanil at gmail.com> wrote: > > The job is very simple: add link at page > > > https://github.com/draperlaboratory/fracture/wiki/How-TableGen%27s-DAGISel-Backend-Works > > into doc page > >

I agree, but I have no experience with LLVM doc. The job is very simple: add link at page https://github.com/draperlaboratory/fracture/wiki/How-TableGen%27s-DAGISel-Backend-Works into doc page http://llvm.org/docs/TableGen/BackEnds.html But how I can do it? On Tue, Jun 3, 2014 at 4:41 PM, Renato Golin <renato.golin at linaro.org> wrote: > Hi Daniil, > > Those look great! I think

It seems that Tablegen is generating intrinsic ID's off by in DAGISel.inc In DAGISel.inc, I have the following pattern: int64_t CN1 = Tmp0->getZExtValue(); // Pattern: (intrinsic_w_chain:f32 103:iPTR, GPRF32:f32:$src0, GPRF32:f32:$src1, GPRF32:f32:$src2) // Emits: (MACRO_FMA_f32:f32 GPRF32:f32:$src0, GPRF32:f32:$src1, GPRF32:f32:$src2) // Pattern complexity = 8 cost

Hi all! There is doc about tglben backends: http://llvm.org/docs/TableGen/BackEnds.html May be should to add link at https://github.com/draperlaboratory/fracture/wiki/How-TableGen%27s-DAGISel-Backend-Works I remember when I first met the LLVM it would be very useful. -------------- next part -------------- An HTML attachment was scrubbed... URL:

I thought I'd share a little bit of progress I made this weekend. I've gotten the first interesting test-case (a simple switch) through hyperblock-based DAGISel, and there's a pretty picture too! Each part of the switch is emitted directly into the DAG, rather than being deferred. This is the function: define i32 @foo(i32 %x, i32 %z) nounwind { entry: switch i32 %x,

Hello. I come back to this older thread. Again, because of i64immSExt32 I receive TableGen error "Could not infer all types in, pattern!" (exact details written below). So far I'm not able to generate selection code with TableGen for the ADD_r* instructions, etc: def i64immSExt32 : PatLeaf<(imm), [{return

Are you using isTarget = 1 in your intrinsics file? On Apr 14, 2009, at 6:34 PM, Villmow, Micah wrote: > It seems that Tablegen is generating intrinsic ID’s off by in > DAGISel.inc > > In DAGISel.inc, I have the following pattern: > int64_t CN1 = Tmp0->getZExtValue(); > > // Pattern: (intrinsic_w_chain:f32 103:iPTR, GPRF32:f32:$src0, > GPRF32:f32:$src1,

I've kicked off a run to compare "-O0 -g" versus "-O0 -g -mllvm -global-isel -mllvm -global-isel-abort=2". I've selected the test-suite (albeit a version which is a couple of months old now) and a few short-running proprietary benchmarks to get data back quickly for an initial feel of where things are. This was running on Cortex-A57 AArch64 Linux. I saw one assertion

Hi All, when looking through all the existing targets, I see that each of them defines <Target>ISelLowering.{cpp,h} files. However, they define a class called "<Target>TargetLowering" (though the comments in [at least some of] those files stay the define "<Target>ISelLowering". I suspect that this class was renamed at some time (which makes sense, since I