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

[Philip Reames via llvm-commits]

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@@ -496,9 +496,9 @@ define float @vreduce_ord_fwadd_v8f32(ptr %x, float %s) {
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    vsetivli zero, 8, e16, m1, ta, ma
 ; CHECK-NEXT:    vle16.v v8, (a0)
-; CHECK-NEXT:    vsetivli zero, 8, e32, m1, ta, ma
+; CHECK-NEXT:    vsetivli zero, 8, e32, m2, ta, ma
 ; CHECK-NEXT:    vfmv.s.f v9, fa0
-; CHECK-NEXT:    vsetivli zero, 8, e16, m1, ta, ma
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preames wrote:

Actually, thinking about this, why can't the forward pass find this case too?  Same reasoning as the previous comment.

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