The list of fused instructions is kinda weird; besides the ones that correspond to SH{1,2,3,4}ADD anyway, I don't think I expected any of the others.
I don't see a mention of Sifive-style short jump predication there either, though I'm using Google Translate.
0. https://old.reddit.com/r/RISCV/comments/1hnm5y1/where_did_th...
Refer to the "base instruction" column in the pseudoinstruction table[0].
0. https://github.com/riscv-non-isa/riscv-asm-manual/blob/main/...
The only other source I know of was this 2016 paper that suggested specific macro fusions. https://arxiv.org/abs/1607.02318 This predates the B extension so some of those fusions are dedicated instructions now, but I suppose Xiangshan still implements them for the sake of software that was not compiled with B enabled.