[llvm] [RISCV] Add a release note about tail folding being enabled. NFC (PR #153535)

[Pengcheng Wang via llvm-commits]

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@@ -109,6 +109,9 @@ Changes to the PowerPC Backend
 Changes to the RISC-V Backend
 -----------------------------
 
+* The loop vectorizer now performs tail folding by default on RISC-V, which
+  removes the need for a scalar epilogue loop. To restore the previous behaviour
+  use `-mllvm -prefer-predicate-over-epilogue=scalar-epilogue`.
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wangpc-pp wrote:

`-mllvm` is needed for `clang`, but not for `opt`/`llc`/... We may not say that in LLVM's release notes. :-)

https://github.com/llvm/llvm-project/pull/153535