[emitc] Fix precedence when emit emit.expression (#124087)

Fixes #124086.

Author: jacquesguan

mlir/lib/Target/Cpp/TranslateToCpp.cpp

@@ -1387,11 +1387,9 @@ LogicalResult CppEmitter::emitOperand(Value value) {
     // as they might be evaluated in the wrong order depending on the shape of
     // the expression tree.
     bool encloseInParenthesis = precedence.value() <= getExpressionPrecedence();
-    if (encloseInParenthesis) {
+    if (encloseInParenthesis)
       os << "(";
-      pushExpressionPrecedence(lowestPrecedence());
-    } else
-      pushExpressionPrecedence(precedence.value());
+    pushExpressionPrecedence(precedence.value());
 
     if (failed(emitOperation(*def, /*trailingSemicolon=*/false)))
       return failure();

mlir/test/Target/Cpp/expressions.mlir

@@ -70,11 +70,11 @@ func.func @do_not_inline(%arg0: i32, %arg1: i32, %arg2 : i32) -> i32 {
 }
 
 // CPP-DEFAULT:      float parentheses_for_low_precedence(int32_t [[VAL_1:v[0-9]+]], int32_t [[VAL_2:v[0-9]+]], int32_t [[VAL_3:v[0-9]+]]) {
-// CPP-DEFAULT-NEXT:   return (float) ([[VAL_1]] + [[VAL_2]] * [[VAL_3]]);
+// CPP-DEFAULT-NEXT:   return (float) (([[VAL_1]] + [[VAL_2]]) * [[VAL_3]]);
 // CPP-DEFAULT-NEXT: }
 
 // CPP-DECLTOP:      float parentheses_for_low_precedence(int32_t [[VAL_1:v[0-9]+]], int32_t [[VAL_2:v[0-9]+]], int32_t [[VAL_3:v[0-9]+]]) {
-// CPP-DECLTOP-NEXT:   return (float) ([[VAL_1]] + [[VAL_2]] * [[VAL_3]]);
+// CPP-DECLTOP-NEXT:   return (float) (([[VAL_1]] + [[VAL_2]]) * [[VAL_3]]);
 // CPP-DECLTOP-NEXT: }
 
 func.func @parentheses_for_low_precedence(%arg0: i32, %arg1: i32, %arg2: i32) -> f32 {