This repository contains the source code for Control-flow Melding (CFM). CFM is a compiler transformation that melds (i.e. merges) isomorphic control-flow regions contained within if and else sections of a conditional branch. CFM transformation is useful for reducing control-flow divergence in GPU programs and reduce code size in CPU programs. This version of CFM is implemented on top of LLVM-14.0.0.
The default apt packages should be enough for Ubuntu >= 19.10. Default packages plus a pre-built cmake should work for Ubuntu >= 18.04. For older systems, you might have to satisfy the dependencies manually.
- cmake (>= 3.13.4 : If your cmake is older than that, install a newer version maually and add it to your path.
- build-essential : This will pull the rest of the dependencies
For more information about LLVM dependencies check the LLVM project page.
Download the code
git clone git@github.com:charitha22/cfm-llvm14.git
git clone git@github.com:llvm/llvm-project.git
Checkout the LLVM-14.0.0 release.
cd llvm-project
git checkout $(cat ../cfm-llvm14/llvm_version.txt)
Apply the patch containing CFM source code changes on top of llvm-14
git apply ../cfm-llvm14/control-flow-melding-pass-with-llvm-14.patch
Build LLVM
bash scripts/run_cmake.sh
bash scripts/build_install.sh
Run examples
export LLVM_HOME=$(pwd)/build
cd cfm_tests/cfg/
make && make test