[llvm] [RISCV] Select and/or/xor with certain constants to Zbb ANDN/ORN/XNOR (PR #120221)

[Piotr Fusik via llvm-commits]

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@@ -273,37 +240,21 @@ define i32 @compl(i32 %x) {
 }
 
 define i32 @orlow12(i32 %x) {
-; RV32-LABEL: orlow12:
-; RV32:       # %bb.0:
-; RV32-NEXT:    lui a1, 1
-; RV32-NEXT:    addi a1, a1, -1
-; RV32-NEXT:    or a0, a0, a1
-; RV32-NEXT:    ret
-;
-; RV64-LABEL: orlow12:
-; RV64:       # %bb.0:
-; RV64-NEXT:    lui a1, 1
-; RV64-NEXT:    addiw a1, a1, -1
-; RV64-NEXT:    or a0, a0, a1
-; RV64-NEXT:    ret
+; CHECK-LABEL: orlow12:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    lui a1, 1048575
+; CHECK-NEXT:    orn a0, a0, a1
+; CHECK-NEXT:    ret
   %or = or i32 %x, 4095
   ret i32 %or
 }
 
 define i32 @xorlow12(i32 %x) {
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pfusik wrote:

Similar to the above.

        xori    a0, a0, 2047
        binvi   a0, a0, 11


https://github.com/llvm/llvm-project/pull/120221