similar to: Replication -O3 optimizations manually

Hi, Stefano I also have the problem as described by Emanuele. You say that clang schedules target-independent and target-dependent passes. However, when I use lli to execute bitcode generated by opt with -O3 or with the same optimization passes as -O3, the performance are still different. So, are there some special operations by -O3 option? I read the source code of opt, but I cannot find the

Hi Zide, I think I found the right way to reach my goal. I used the following command: clang -O3 -Xclang -disable-llvm-optzns main.c -S -emit-llvm -o main.ll to generate an IR file enriched by all the metadata that otherwise wouldn't be generated with -O0. Moreover, -disable-llvm-optzns flag ensures that none of the optimization passes has been applied yet to the IR. In this way, I can

Dear developers, I am trying to reproduce the results of applying opt -O3 to a source file in the form of LLVM IR. I want to get the same IR by manually ordering the passes used by O3 and passing them to opt. To illustrate what I am doing on an example, as an input I use linpack benchmark from the LLVM test suite[1]: 1. First I produce the intermediate representation using clang: clang -O3

I think this has to do with how the pass manager is populated when we give -O3 vs when we give particular pass names. Some passes have multiple createXYZPass() methods that accept arguments too. These methods call non-default pass constructors, which in turn cause the passes to behave in a different manner. eg: Pass *llvm::createLICMPass() { return new LegacyLICMPass(); } Pass

Hi all, is there any Italian developer that can be interested in a LLVM social event/meetup in Italy? Best, --- Marco Bambini http://creolabs.com http://twitter.com/sqlabs

Hello, I want to study the individual O3 optimizations. For this I am using following commands, but unable to replicate O3 behavior. 1. Documents/clang+llvm-9.0.0-x86_64-linux-gnu-ubuntu-18.04/bin/clang -O1 -Xclang -disable-llvm-passes -emit-llvm -S vecsum.c -o vecsum-noopt.ll 2. Documents/clang+llvm-9.0.0-x86_64-linux-gnu-ubuntu-18.04/bin/clang -O3 -mllvm -debug-pass=Arguments -emit-llvm -S

On Thu, Oct 17, 2019 at 11:22 AM David Greene via llvm-dev < llvm-dev at lists.llvm.org> wrote: > hameeza ahmed via llvm-dev <llvm-dev at lists.llvm.org> writes: > > > Hello, > > I want to study the individual O3 optimizations. For this I am using > > following commands, but unable to replicate O3 behavior. > > > > 1.

Thanks again. I executed the following command line llc -O3 comb.ll.bc -debug-pass=Arguments and got Pass Arguments: -targetdata -targetpassconfig -no-aa -tbaa -targetlibinfo -basicaa -collector-metadata -machinemoduleinfo -machine-branch-prob -preverify -domtree -verify -loops -loop-simplify -scalar-evolution -loop-simplify -iv-users -loop-reduce -gc-lowering -unreachableblockelim

I run matrix multiplication code with both the approaches o3 at clang and o3 at opt. clang o3 is about 2.97x faster than opt o3. On Mon, Oct 21, 2019 at 8:24 AM Neil Nelson <nnelson at infowest.com> wrote: > is_sorted.cpp > bool is_sorted(int *a, int n) { > > for (int i = 0; i < n - 1; i++) > > if (a[i] > a[i + 1]) > return false; > return

Hi, > I executed the following command line > > llc -O3 comb.ll.bc -debug-pass=Arguments > > and got > > Pass Arguments: -targetdata -targetpassconfig -no-aa -tbaa > -targetlibinfo -basicaa -collector-metadata -machinemoduleinfo > -machine-branch-prob -preverify -domtree -verify -loops -loop-simplify > -scalar-evolution -loop-simplify -iv-users -loop-reduce

Hi, Similar questions have come up before on the list and elsewhere but I haven't found a solution yet. winbuilder's install.out shows data.table's .c files compiled with -O3 on Win32 but -O2 on Win64. The same happens on R-Forge. I gather that some packages don't work with -O3 so the default is -O2. I've tried this in data.table's Makevars (entire contents) : ====

Hello, I've been trying to figure out how to reproduce the results of a single clang -O3 compilation to a binary with a multi-step process using opt. Specifically I have: clang -O3 foo.c -o foo.exe which I want to replicate with: clang -O0 -c -emit-llvm foo.c opt -O3 foo.bc -o foo_o.bc clang foo_o.bc -o foo.exe Any hints / suggestions on what additional flags I need to produce the same

This is probably a trivial question but the way I used to do this turns out to be flawed. I used run clang with -O0 -emit-llvm and then use the resulting IR with opt -O3. The problem is that clang at -O0 does not generate TBAA metadata so the passes run by opt behave differently. What’s the recommended way of doing this? Thanks, Adam

Awesome, thanks! I'd like to have the last step (llc in your example) not perform additional optimization passes, such as O3, and simply use the O3 pass from opt in the previous line. Do you happen to know if I should use 'llc -O0 foo_o.bc -o foo.exe' instead to achieve this? On Thu, Jul 2, 2020 at 6:35 PM Mehdi AMINI <joker.eph at gmail.com> wrote: > > > On Thu,

Hello, I'm trying to minimize the processing time for llc -O3 by using a three step compilation process of 1. llc input.bc -stopafter=targetlibinfo -o input.mir 2. llc -run-pass={....min passes...} input.mir -o opt.mir 3. llc -startafter=machine-opt-remark-emitter -filetype=obj opt.mir -o final.obj Examining the passes produced by llc for O1,O2,O3 I compared (with XXX = {1,2,3}): llc

Thanks alot. How can we view those optimization which are enabled when we do llc -O3 comb.ll Are these the same as the ones produced by the following command line llvm-as < /dev/null | opt -O3 -disable-output -debug-pass=Arguments Regards Shahzad On Tue, Jun 12, 2012 at 1:01 PM, Duncan Sands <baldrick at free.fr> wrote: >> Yes. But how exactly code generation (optimized one)

Hi, On 12/06/12 13:09, Abdul Wahid Memon wrote: > Thanks alot. How can we view those optimization which are enabled when we do > > llc -O3 comb.ll llc -O3 comb.ll -debug-pass=Arguments > > Are these the same as the ones produced by the following command line no, as I mentioned before they are of a completely different nature to the optimizations that opt does. Ciao, Duncan.

Hello, I am trying out the LoopVectorizer(LV) pass and would like to decouple it from O3 which is currently required to run LV. I want to do this because I want to understand the behaviour of LV by trying simple loops but the O3 mostly optimises away the loop body. Any ideas would be appreciated. Best, Anadi. -------------- next part -------------- An HTML attachment was scrubbed... URL:

I've been playing with compilation options to try and improve response times, I haven't compiled the results, which in hindsight I now realise I should have! (Never mind!) However, I have got the following results building with GCC 4.5.1: gcc -O3 Works fine gcc -march=barcelona Works fine gcc -O2 -march=barcelona -fgcse-after-reload -finline-functions -fipa_cp_clone

When I compile my C fibonacci example fib.c with 'clang -O3 -c -emit-llvm -o fib-clang.bc fib.c&& llvm-dis fib-clang.bc' I get fib-clang.ll that has some degree of inlining in it. But when I get an equivalent to fib.c file fib.ll and run it through opt with the command 'llvm-as fib.ll&& opt -O3 fib.bc -o fib-opt.bc&& llvm-dis fib-opt.bc' resulting