[llvm] [RISCV][ISel] Combine scalable vector add/sub/mul with zero/sign extension (PR #72340)

[via llvm-commits]

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@@ -1231,16 +1231,17 @@ define <vscale x 1 x i64> @ctlz_nxv1i64(<vscale x 1 x i64> %va) {
 ;
 ; CHECK-F-LABEL: ctlz_nxv1i64:
 ; CHECK-F:       # %bb.0:
-; CHECK-F-NEXT:    vsetvli a0, zero, e32, mf2, ta, ma
+; CHECK-F-NEXT:    li a0, 190
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sun-jacobi wrote:

Here `vrsub.vx` and `vzext.vf2` are folded into  `vwsubu.wv`. 

https://github.com/llvm/llvm-project/pull/72340