[llvm] [RISCV] Fold LI 1 / SLLI into BSETI during i64 materialization (PR #142348)

[Piotr Fusik via llvm-commits]

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@@ -397,18 +397,27 @@ define i64 @and_or_or(i64 %x, i64 %y) {
 ; RV32-NEXT:    and a1, a1, a3
 ; RV32-NEXT:    ret
 ;
-; RV64-LABEL: and_or_or:
-; RV64:       # %bb.0:
-; RV64-NEXT:    li a2, -1
-; RV64-NEXT:    slli a2, a2, 33
-; RV64-NEXT:    addi a2, a2, 1
-; RV64-NEXT:    or a0, a0, a2
-; RV64-NEXT:    li a2, 1
-; RV64-NEXT:    slli a2, a2, 33
-; RV64-NEXT:    addi a2, a2, -2
-; RV64-NEXT:    or a1, a1, a2
-; RV64-NEXT:    and a0, a0, a1
-; RV64-NEXT:    ret
+; NOZBS64-LABEL: and_or_or:
+; NOZBS64:       # %bb.0:
+; NOZBS64-NEXT:    li a2, -1
+; NOZBS64-NEXT:    slli a2, a2, 33
+; NOZBS64-NEXT:    addi a2, a2, 1
+; NOZBS64-NEXT:    or a0, a0, a2
+; NOZBS64-NEXT:    li a2, 1
+; NOZBS64-NEXT:    slli a2, a2, 33
+; NOZBS64-NEXT:    addi a2, a2, -2
+; NOZBS64-NEXT:    or a1, a1, a2
+; NOZBS64-NEXT:    and a0, a0, a1
+; NOZBS64-NEXT:    ret
+;
+; ZBS64-LABEL: and_or_or:
+; ZBS64:       # %bb.0:
+; ZBS64-NEXT:    bseti a2, zero, 33
+; ZBS64-NEXT:    addi a2, a2, -2
+; ZBS64-NEXT:    orn a0, a0, a2
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pfusik wrote:

Combines nicely with #120221. Found in https://github.com/dtcxzyw/llvm-codegen-benchmark/blob/aad2b0e07e06107067bab0a1b6aeaeef3897b95a/dataset/3decd43ca8a5d573.ll#L18

https://github.com/llvm/llvm-project/pull/142348