similar to: [LLVMdev] Is "clang -O1" the same as "clang -O0 + opt -O1"?

Can I specify passes that I want run directly to llvm-gcc? I don't want all of -O3, for example. I tried llvm-gcc -raiseallocs ..., but that didn't work. I also tried running cc1 directly and it didn't take -raiseallocs as a parameter either. Duncan Sands wrote: > On Tuesday 28 April 2009 04:02:47 am Ryan M. Lefever wrote: >> I assume that when -O3 (or O2 or O1) is

Thanks for the help. When I run the following (where $llvm is the path to my llvm installation): $llvm/bin/llvm-gcc -c -o - -O1 tmp.c -emit-llvm -mllvm --disable-llvm-optzns | $llvm/bin/opt -raiseallocs I get the following error: cc1: error: unrecognized command line option "-fdisable-llvm-optzns" I am running llvm 2.5. I performed a $llvm/libexec/gcc/i686-pc-linux-gnu/4.2.1/cc1

Hello, I m trying to test individual O3 optimizations/ replicating O3 behavior on IR. I took unoptimized IR (O0), used disable-o0-optnone via (*clang -O0 -Xclang -disable-O0-optnone*). I read somewhere about *clang -O1 -Xclang -disable-O0-optnone,* so I also tested on this initial IR. I have observed by using individual optimizations, the performance (i.e time) is better when the base/initial

On Tuesday 28 April 2009 09:19:19 am Ryan M. Lefever wrote: > Can I specify passes that I want run directly to llvm-gcc? I don't want > all of -O3, for example. I tried llvm-gcc -raiseallocs ..., but that > didn't work. I also tried running cc1 directly and it didn't take > -raiseallocs as a parameter either. You are better off run passes explicitly using opt. Try

Hi all, I am trying to understand the effectiveness of various llvm optimisations when a language targets llvm (or C) as its backend. The following is my approach (please correct me if I did anything wrong): I am trying to explicitly control the optimisations passes in llvm. I disable optimisation in clang, but instead emit unoptimized llvm IR, and use opt to optimise that. These are what I

On Oct 8, 2011, at 12:05 PM, Duncan Sands wrote: > PS: With -fplugin-arg-dragonegg-enable-gcc-optzns the LLVM optimizers are run at > the following levels: > > Command line option LLVM optimizers run at > ------------------- ---------------------- > -O1 tiny amount of optimization > -O2 or -O3 -O1 > -O4 or -O5

Have -O0 on your clang command line causes all functions to get marked with an 'optnone' attribute that prevents opt from being able to optimize them later. You should also add "-Xclang -disable-O0-optnone" to your command line. ~Craig On Thu, Sep 21, 2017 at 10:04 PM, Yi Lin via llvm-dev < llvm-dev at lists.llvm.org> wrote: > Hi all, > > I am trying to

Duncan, Below are the tabulated compile times and executable sizes. A) gcc 4.5.4svn using -msse3 -ffast-math -O3 -fno-tree-vectorize B) gcc 4.5.4svn/dragonegg using -msse3 -ffast-math -O3 -fno-tree-vectorize -fplugin-arg-dragonegg-enable-gcc-optzns C) gcc 4.5.4svn/dragonegg using -msse3 -ffast-math -O3 -fno-tree-vectorize Compile time (seconds) Benchmark A) stock B) gcc 4.5.4/ C)

Hi, I would like to run the -O1 pass sequence followed by -reg2mem from an out of tree project which uses llvm. I am using the following code snippet to do so but in some cases, my method is also vectorising the code, which doesn't happen when running the same sequence(-S -O1 -reg2mem) through opt. Can someone please help me find what I am missing? Thanks, Akash. *

Hi Jack, thanks for doing this. > Below are the tabulated compile times and executable sizes. > > A) gcc 4.5.4svn using -msse3 -ffast-math -O3 -fno-tree-vectorize > B) gcc 4.5.4svn/dragonegg using -msse3 -ffast-math -O3 -fno-tree-vectorize -fplugin-arg-dragonegg-enable-gcc-optzns > C) gcc 4.5.4svn/dragonegg using -msse3 -ffast-math -O3 -fno-tree-vectorize These numbers really

Hi Chris, >> PS: With -fplugin-arg-dragonegg-enable-gcc-optzns the LLVM optimizers are run at >> the following levels: >> >> Command line option LLVM optimizers run at >> ------------------- ---------------------- >> -O1 tiny amount of optimization >> -O2 or -O3 -O1 >> -O4 or -O5

Hello, I have already asked how to receive unoptimized IR. This way: clang -S -emit-llvm -O3 -mllvm -disable-llvm-optzns memset.c -o memset.s I have noticed, that in any case, when I use O1, O2, O3 and disable optimizations, I still get llvm intrinsics functions inserted. when I put O0, I have no intrinsics, but have noopt attribute. Is there a way to receive purely unoptimizaed IR without any

I have a piece of C code, and when I compile it to bitcode using llvm-gcc with -O3, the result is different than if I compile using llvm-gcc with no optimization, but pipe the output to opt running the same passes as -O3 uses. In particular, llvm-gcc with -O3 leads to int-to-ptr casts while the optimization performed by opt does not. Why are the two methods different, and how do they

Hello all, I have a question related to noduplicate attribute. For example, if I have the following source code: __attribute__((noduplicate)) __attribute__((always_inline)) void wait () { // some code barrier(); // some code } __attribute__((noduplicate)) void barrier (); void f () { // some code wait(); // some code } Sometimes I observed a phenomenon that

The Polyhedron 2005 benchmark results for dragonegg svn at r141492 using FSF gcc 4.6.2svn measured on x86_64-apple-darwin11 are listed below. The benchmarks used the optimizaton flags... -msse4 -ffast-math -funroll-loops -O3 in all cases. The use of -fplugin-arg-dragonegg-enable-gcc-optzns to allow for autovectorization from the FSF gcc front-end only produces a single run-time regression,

On Thu, Jun 09, 2011 at 08:47:26PM -0400, Jack Howarth wrote: > Duncan, > Here are the complete benchmarks rerun against gcc 4.5.4 built with... > > Using built-in specs. > COLLECT_GCC=gfortran-fsf-4.5 > COLLECT_LTO_WRAPPER=/sw/lib/gcc4.5/libexec/gcc/x86_64-apple-darwin11.0.0/4.5.4/lto-wrapper > Target: x86_64-apple-darwin11.0.0 > Configured with:

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 Wed, Oct 12, 2011 at 09:40:53AM +0200, Duncan Sands wrote: > Hi Chris, > >>> PS: With -fplugin-arg-dragonegg-enable-gcc-optzns the LLVM optimizers are run at >>> the following levels: >>> >>> Command line option LLVM optimizers run at >>> ------------------- ---------------------- >>> -O1 tiny amount of

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.

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