[llvm] [SDAG] Use shifts if ISD::MUL is illegal when lowering ISD::CTPOP (PR #86505)

[Wang Pengcheng via llvm-commits]

================
@@ -197,8 +196,14 @@ define void @test5(i32 signext %arg, i32 signext %arg1) nounwind {
 ; RV64I-NEXT:    add a0, a2, a0
 ; RV64I-NEXT:    srli a2, a0, 4
 ; RV64I-NEXT:    add a0, a0, a2
-; RV64I-NEXT:    and a0, a0, s2
-; RV64I-NEXT:    mul a0, a0, s3
+; RV64I-NEXT:    and a2, a0, s2
----------------
wangpc-pp wrote:

And here.

https://github.com/llvm/llvm-project/pull/86505