[llvm-branch-commits] [llvm] backport: [RISCV] Sources of vmerge shouldn't overlap V0 (#170070) (PR #170604)

[Pengcheng Wang via llvm-branch-commits]

wangpc-pp wrote:

> > Hi @asb, @topperc and @preames, I'm a bit hesitant to take this fix into the release branch because it seems a bit large for what is essentially the last release of the 21.x branch. After this there will be no more releases, so no chances to fix any issues that may arise. The fact that one was already found when backporting the fix makes me even more worried. As the owners of the RISCV backend, do any of you have any thoughts on how risky it would be to take this fix in 21.x or should we just wait for the 22.x branch for the fix?
> 
> @lukel97 @wangpc-pp Is the change to RISCVInstrInfoVPseudos.td enough to fix the bug? Was the RISCVVectorPeephole.cpp part for correctness or to prevent regressions?

But I think the regression can be large. :-(

https://github.com/llvm/llvm-project/pull/170604