[mlir][emitc] Ignore literal in form-expression

Literal is always inlined, so there's no need to form expressions
with it as well.

Author: Vladislave0-0

mlir/lib/Dialect/EmitC/Transforms/FormExpressions.cpp

@@ -38,7 +38,7 @@ struct FormExpressionsPass
     auto matchFun = [&](Operation *op) {
       if (isa<emitc::CExpressionInterface>(*op) &&
           !op->getParentOfType<emitc::ExpressionOp>() &&
-          op->getNumResults() == 1)
+          !isa<emitc::LiteralOp>(op) && op->getNumResults() == 1)
         createExpression(op, builder);
     };
     rootOp->walk(matchFun);

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

@@ -192,6 +192,7 @@ func.func @opaque_type_expression(%arg0: i32,  %arg1: !emitc.opaque<"T0">, %arg2
   %c = emitc.cmp lt, %b, %arg2 :(i32, i32) -> i1
   return %c : i1
 }
+<<<<<<< HEAD
 
 // CHECK-LABEL:   func.func @expression_with_constant(
 // CHECK-SAME:                                        %[[VAL_0:.*]]: i32) -> i32 {
@@ -228,3 +229,5 @@ func.func @expression_with_literal(%arg0: i32) -> i1 {
   %c = emitc.cmp lt, %b, %arg0 :(i32, i32) -> i1
   return %c : i1
 }
+=======
+>>>>>>> 6a27d24c62dd ([mlir][emitc] Ignore literal in form-expression)

mlir/test/Target/Cpp/expressions.mlir

@@ -472,7 +472,7 @@ emitc.func @expression_with_call_opaque_with_args_array(%0 : i32, %1 : i32) {
 // CPP-DECLTOP-NEXT: }
 
 func.func @expression_with_literal(%arg0 : i32) -> i1 {
-  %ret = emitc.expression noinline : i1 {
+  %ret = emitc.expression %arg0 noinline : (i32) -> i1 {
     %literal1 = emitc.literal "1" : i32
     %literal2 = emitc.literal "2" : i32
     %add = add %literal1, %arg0 : (i32, i32) -> i32
@@ -495,9 +495,9 @@ func.func @expression_with_literal(%arg0 : i32) -> i1 {
 // CPP-DECLTOP-NEXT: }
 
 func.func @single_literal_in_expression() -> i32 {
-  %result = emitc.expression : i32 {
-    %lit = emitc.literal "42" : i32
-    emitc.yield %lit : i32
+  %ret = emitc.expression : () -> i32 {
+    %literal = emitc.literal "42" : i32
+    emitc.yield %literal : i32
   }
-  return %result : i32
+  return %ret : i32
 }