[MLIR][CF] Fix cf.switch parsing with result numbers (#87658)

This PR should fix the parsing bug reported in
#87430. It allows using
result number as the `cf.switch` operand.

Author: Kuree

mlir/lib/Dialect/ControlFlow/IR/ControlFlowOps.cpp

@@ -531,8 +531,8 @@ static ParseResult parseSwitchOpCases(
         failed(parser.parseSuccessor(destination)))
       return failure();
     if (succeeded(parser.parseOptionalLParen())) {
-      if (failed(parser.parseOperandList(operands, OpAsmParser::Delimiter::None,
-                                         /*allowResultNumber=*/false)) ||
+      if (failed(parser.parseOperandList(operands,
+                                         OpAsmParser::Delimiter::None)) ||
           failed(parser.parseColonTypeList(operandTypes)) ||
           failed(parser.parseRParen()))
         return failure();

mlir/test/Dialect/ControlFlow/ops.mlir

@@ -38,3 +38,16 @@ func.func @switch_i64(%flag : i64, %caseOperand : i32) {
   ^bb3(%bb3arg : i32):
     return
 }
+
+// CHECK-LABEL: func @switch_result_number
+func.func @switch_result_number(%arg0: i32) {
+  %0:2 = "test.op_with_two_results"() : () -> (i32, i32)
+  cf.switch %arg0 : i32, [
+    default: ^bb2,
+    0: ^bb1(%0#0 : i32)
+  ]
+  ^bb1(%1: i32):
+    return
+  ^bb2:
+    return
+}