This is the RISC-V Vector Extension support in LLVM and CLANG implemented by Hunan Compiler Information Technology Co., Ltd (http://www.compiler-dev.com, Email: info@compiler-dev.com). So far the compiler has been compatible with the Riscv-v-spec-0.8. Please add isa=rv32imafcv and vlen=128 options to the command line as compiling source codes.

This implementation includes Clang C/C++ compiler, llvm-mc assembler, and llvm-objdump disassembler. The RISC-V Vector Extension module is fully supported using more than 6000 intrinsic interfaces.

The README briefly describes how to get started with building LLVM and CLANG, and how to run a rvv test in spike on a linux x86 machine as an example.

This compiler depends on the GNU ld, newlib, and libgcc. If you'd like to run the compiled program on a emulator, the SPIKE is also needed. We provide these pre-compiled binaries for linux x86 platform.

https://github.com/compiler-dev/rvvtool-chain-binaries

You could also build these tools from the source codes by the following steps. Suppose that the path of the rvvtool-chain-binaries is TOOL_CHAIN_PATH.

1. Build riscv-gnu-toolchain

• $ git clone https://github.com/riscv/riscv-gnu-toolchain
• $ cd riscv-gnu-toolchain
• $ git submodule update --init --recursive
• $ ./configure --with-arch=rv32imafc --with-abi=ilp32 --prefix=$TOOL_CHAIN_PATH
• $ make

2. Build spike

• $ git clone https://github.com/riscv/riscv-isa-sim.git
• $ apt-get install device-tree-compiler
• $ mkdir spike-build
• $ cd spike-build
• $ ../riscv-isa-sim-master/configure --with-varch=vlen:128,elen:32,slen:128 --with-isa=rv32imafcv
  --prefix=$TOOL_CHAIN_PATH
• $ make && make install

3. Build riscv pk

• $ git clone https://github.com/riscv/riscv-pk.git
• $ mkdir pk-build
• $ cd pk-build
• $ export PATH=$TOOL_CHAIN_PATH/bin:$PATH
• $ export CFLAGS=-D__riscv_compressed
• $ ../riscv-pk/configure --host=riscv32-unknown-elf --with-arch=rv32i --prefix=$TOOL_CHAIN_PATH
  CC=riscv32-unknown-elf-gcc
• $ make && make install

• $ git clone https://github.com/compiler-dev/llvm-rv.git
• $ cd llvm-rv
• $ git checkout vector
• $ mkdir build
• $ cd build
• $ cmake -G "Unix Makefiles" -DLLVM_TARGETS_TO_BUILD="RISCV"
  -DLLVM_DEFAULT_TARGET_TRIPLE=riscv32-unknown-elf
  -DCMAKE_BUILD_TYPE=Release -DDEFAULT_SYSROOT=$TOOL_CHAIN_PATH/riscv32-unknown-elf
  -DLLVM_ENABLE_PROJECTS=clang -DCMAKE_INSTALL_PREFIX=$TOOL_CHAIN_PATH ../llvm
• $ make && make install

• $ export PATH=$TOOL_CHAIN_PATH/bin:$PATH

• $ cd llvm-rv/rvv-test

• $ clang vadd_vv_i32.c -O2 --target=riscv32 -march=rv32imafcv --sysroot=$TOOL_CHAIN_PATH/riscv-unknown-elf
  --gcc-toolchain=$TOOL_CHAIN_PATH -o vadd_vv_i32.out

• $ spike $TOOL_CHAIN_PATH/riscv32-unknown-elf/bin/pk ./vadd_vv_i32.out

• Output:
  Expect:
  {0x7fffffff,0x80000001,0x80000003,0x80000005}
  Actual:
  {0x7fffffff,0x80000001,0x80000003,0x80000005}
  pass!

If the program uses the floating-point instructions, the FPU should be enabled by replacing some files in the rvvtool-chain-binaries.

• $ cp -r $TOOL_CHAIN_PATH/enable-fp/usr $TOOL_CHAIN_PATH/

The following example comes from RISC-V Vector Extension Intrinsic Document (https://github.com/riscv/rvv-intrinsic-doc) with minor changes conforming to Riscv-v-spec-0.8.

• $ clang llvm-rv/rvv-test/rvv_sgemm.c -O2 --target=riscv32 -march=rv32imafcv --sysroot=$TOOL_CHAIN_PATH/riscv32-unknown-elf --gcc-toolchain=$TOOL_CHAIN_PATH -nodefaultlibs -Wl,--start-group -lc -lgcc -lm -lsim -Wl, --end-group
  -T $TOOL_CHAIN_PATH/bin/link.ld -o rvv_sgemm.out
• $ spike -m0x10000000:0x200000 ./rvv_sgemm.out

#Note In the rvv-test directory, there are two directories besides three testcases which could be run in SPIKE.

• intrinsic: Intrinsic APIs test cases.
• KmplIntrinsicAPI: Documents for more than 6,000 intrinsic APIs. You could begin with riscv_vector.h.html.