[llvm] [RISCV][VLOPT] Enable the RISCVVLOptimizer by default (PR #119461)

[Michael Maitland via llvm-commits]

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@@ -97,8 +97,9 @@ define <4 x i32> @v4i32_v8i32(<8 x i32>) {
 define <4 x i32> @v4i32_v16i32(<16 x i32>) {
 ; RV32-LABEL: v4i32_v16i32:
 ; RV32:       # %bb.0:
-; RV32-NEXT:    vsetivli zero, 8, e16, m1, ta, ma
+; RV32-NEXT:    vsetivli zero, 2, e16, m1, ta, ma
 ; RV32-NEXT:    vmv.v.i v12, 1
+; RV32-NEXT:    vsetivli zero, 8, e16, m1, ta, ma
 ; RV32-NEXT:    vmv.v.i v14, 6
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michaelmaitland wrote:

Take a look at the MIR: https://godbolt.org/z/xrvG13qx6

You can see that `%4` is used as a tied operand.

https://github.com/llvm/llvm-project/blob/644643a4ee931ce24c27702851a93160cf0f1248/llvm/lib/Target/RISCV/RISCVVLOptimizer.cpp#L917

https://github.com/llvm/llvm-project/pull/119461