[mlir][emitc] Changes after review

Author: Vladislave0-0

mlir/include/mlir/Dialect/EmitC/IR/EmitC.td

@@ -896,6 +896,12 @@ def EmitC_LiteralOp : EmitC_Op<"literal", [Pure, CExpressionInterface]> {
 
   let hasVerifier = 1;
   let assemblyFormat = "$value attr-dict `:` type($result)";
+
+  let extraClassDeclaration = [{
+    bool hasSideEffects() {
+      return false;
+    }
+  }];
 }
 
 def EmitC_LogicalAndOp : EmitC_BinaryOp<"logical_and", []> {

mlir/lib/Target/Cpp/TranslateToCpp.cpp

@@ -100,7 +100,7 @@ static FailureOr<int> getOperatorPrecedence(Operation *operation) {
       .Case<emitc::ConstantOp>([&](auto op) { return 17; })
       .Case<emitc::DivOp>([&](auto op) { return 13; })
       .Case<emitc::LoadOp>([&](auto op) { return 16; })
-      .Case<emitc::LiteralOp>([&](auto op) { return 16; })
+      .Case<emitc::LiteralOp>([&](auto op) { return 17; })
       .Case<emitc::LogicalAndOp>([&](auto op) { return 4; })
       .Case<emitc::LogicalNotOp>([&](auto op) { return 15; })
       .Case<emitc::LogicalOrOp>([&](auto op) { return 3; })

mlir/test/Dialect/EmitC/form-expressions.mlir

@@ -211,20 +211,14 @@ func.func @expression_with_constant(%arg0: i32) -> i32 {
 
 // CHECK-LABEL:   func.func @expression_with_literal(
 // CHECK-SAME:      %[[ARG0:.*]]: i32) -> i1 {
-// CHECK:           %[[VAL_0:.*]] = emitc.expression : i32 {
+// CHECK:           %[[VAL_0:.*]] = emitc.expression : i1 {
 // CHECK:             %[[VAL_1:.*]] = literal "1" : i32
-// CHECK:             yield %[[VAL_1]] : i32
+// CHECK:             %[[VAL_2:.*]] = literal "2" : i32
+// CHECK:             %[[VAL_3:.*]] = add %[[VAL_1]], %[[VAL_2]] : (i32, i32) -> i32
+// CHECK:             %[[VAL_4:.*]] = cmp lt, %[[VAL_3]], %[[ARG0]] : (i32, i32) -> i1
+// CHECK:             yield %[[VAL_4]] : i1
 // CHECK:           }
-// CHECK:           %[[VAL_2:.*]] = emitc.expression : i32 {
-// CHECK:             %[[VAL_3:.*]] = literal "2" : i32
-// CHECK:             yield %[[VAL_3]] : i32
-// CHECK:           }
-// CHECK:           %[[VAL_4:.*]] = emitc.expression : i1 {
-// CHECK:             %[[VAL_5:.*]] = add %[[VAL_0]], %[[VAL_2]] : (i32, i32) -> i32
-// CHECK:             %[[VAL_6:.*]] = cmp lt, %[[VAL_5]], %[[ARG0]] : (i32, i32) -> i1
-// CHECK:             yield %[[VAL_6]] : i1
-// CHECK:           }
-// CHECK:           return %[[VAL_4]] : i1
+// CHECK:           return %[[VAL_0]] : i1
 // CHECK:         }
 
 func.func @expression_with_literal(%arg0: i32) -> i1 {

mlir/test/Target/Cpp/expressions.mlir

@@ -484,3 +484,20 @@ func.func @expression_with_literal(%arg0 : i32) -> i1 {
 
   return %ret : i1
 }
+
+
+// CPP-DEFAULT:      int32_t single_literal_in_expression() {
+// CPP-DEFAULT-NEXT:   return 42;
+// CPP-DEFAULT-NEXT: }
+
+// CPP-DECLTOP:      int32_t single_literal_in_expression() {
+// CPP-DECLTOP-NEXT:   return 42;
+// CPP-DECLTOP-NEXT: }
+
+func.func @single_literal_in_expression() -> i32 {
+  %result = emitc.expression : i32 {
+    %lit = emitc.literal "42" : i32
+    emitc.yield %lit : i32
+  }
+  return %result : i32
+}