[llvm] [SelectionDAG][RISCV] (add (vscale * C0), (vscale * C1)) to (vscale * (C0 + C1)) in getNode. (PR #144565)

[Craig Topper via llvm-commits]

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@@ -309,10 +308,10 @@ define <vscale x 16 x i8> @insert_nxv16i8_nxv1i8_3(<vscale x 16 x i8> %vec, <vsc
 ; CHECK-LABEL: insert_nxv16i8_nxv1i8_3:
 ; CHECK:       # %bb.0:
 ; CHECK-NEXT:    csrr a0, vlenb
-; CHECK-NEXT:    srli a0, a0, 3
-; CHECK-NEXT:    slli a1, a0, 1
-; CHECK-NEXT:    add a1, a1, a0
-; CHECK-NEXT:    add a0, a1, a0
+; CHECK-NEXT:    srli a1, a0, 3
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topperc wrote:

This uses more registers, but is a shorter critical path.

https://github.com/llvm/llvm-project/pull/144565