[llvm] [RISCV] Emit VP strided loads/stores in RISCVGatherScatterLowering (PR #98111)

[Luke Lau via llvm-commits]

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@@ -144,9 +144,9 @@ define void @gather_zero_stride(ptr noalias nocapture %A, ptr noalias nocapture
 ; CHECK-NEXT:    vsetvli zero, a3, e8, m1, ta, ma
 ; CHECK-NEXT:  .LBB3_1: # %vector.body
 ; CHECK-NEXT:    # =>This Inner Loop Header: Depth=1
-; CHECK-NEXT:    lbu a3, 0(a1)
-; CHECK-NEXT:    vle8.v v8, (a0)
-; CHECK-NEXT:    vadd.vx v8, v8, a3
+; CHECK-NEXT:    vlse8.v v8, (a1), zero
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lukel97 wrote:

In #97798 I had to make sure to use build_vector for fixed-length vectors and splat_vector for scalable vectors.

For CodeGenPrepare does using `IRBuilder::CreateVectorSplat` help? I presume that would get lowered to build_vector and splat_vector for fixed-length and scalable vectors respectively.

https://github.com/llvm/llvm-project/pull/98111