[llvm] Reland "[RISCV][TTI] Enable masked interleave access for scalable vector (#149981)" (PR #151665)

[Luke Lau via llvm-commits]

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@@ -1378,7 +1378,9 @@ class LoopVectorizationCostModel {
       return;
     // Override EVL styles if needed.
     // FIXME: Investigate opportunity for fixed vector factor.
+    // FIXME: Support interleave accesses.
     bool EVLIsLegal = UserIC <= 1 && IsScalableVF &&
+                      !InterleaveInfo.hasGroups() &&
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lukel97 wrote:

I don't think we need to bail on EVL anymore either, https://github.com/llvm/llvm-project/pull/150202 has landed and should fix the concern about the header mask

https://github.com/llvm/llvm-project/pull/151665