[RISCV] Does "V" Extention come with "F" "D" "Zfh" Extentions?

Hi all,
When I tried to run “opt -loop-vectorize” on a testcase, an “UNREACHABLE executed” error was received.
The full command is “./build/bin/opt -loop-vectorize -dce -instcombine -mtriple riscv64-linux-gnu -mattr=+experimental-v -debug-only=loop-vectorize -S llvm/test/Transforms/LoopVectorize/RISCV/basic-vec.ll”(basic-vec.ll as attachment).
Missing “+f” in “-mattr” is the reason of “UNREACHABLE executed” error.
The command “./build/bin/opt -loop-vectorize -dce -instcombine -mtriple riscv64-linux-gnu -mattr=+experimental-v,+f -debug-only=loop-vectorize -S llvm/test/Transforms/LoopVectorize/RISCV/basic-vec.ll” works well.
So can we assume that if a target has StdExtF, it also has StdExtF, StdExtD and StdExtZfh?

basic-vec.ll (4.25 KB)


There is no such implication between V and F/D/Zfh. If you want to use the vector unit to process float/double/fp16 data, you need to specify F, D and Zfh accordingly.


We need to add a TTI interface and vectorizer changes for it to know which element types are legal to make scalable vectors for. AArch64 has a similar problem with at least __int128. https://godbolt.org/z/r38c1Mdfv