[llvm] [RISCV] Adjust LMUL if not used to avoid VL toggle (PR #69259)

[Philip Reames via llvm-commits]

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@@ -1271,11 +1271,11 @@ define void @mscatter_baseidx_sext_v8i8_v8i16(<8 x i16> %val, ptr %base, <8 x i8
 ; RV64ZVE32F-NEXT:    andi a2, a1, 16
 ; RV64ZVE32F-NEXT:    beqz a2, .LBB19_7
 ; RV64ZVE32F-NEXT:  .LBB19_14: # %cond.store7
-; RV64ZVE32F-NEXT:    vsetivli zero, 1, e8, mf4, ta, ma
+; RV64ZVE32F-NEXT:    vsetivli zero, 1, e8, mf2, ta, ma
 ; RV64ZVE32F-NEXT:    vmv.x.s a2, v10
 ; RV64ZVE32F-NEXT:    slli a2, a2, 1
 ; RV64ZVE32F-NEXT:    add a2, a0, a2
-; RV64ZVE32F-NEXT:    vsetivli zero, 1, e16, m1, ta, ma
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preames wrote:

Why isn't this already a VTYPE toggle from the forward pass?  Having the same literal VL and knowing that VL is less than VLMAX for both should be sufficient?

https://github.com/llvm/llvm-project/pull/69259