if (isReturnExpressBlock(thenBranch) && isReturnExpressBlock(elseBranch)) {
Node thenExpr = getBlockReturnExpression(thenBranch);
Node elseExpr = getBlockReturnExpression(elseBranch);
n.removeChild(placeholder);
thenExpr.detachFromParent();
elseExpr.detachFromParent();
// note - we ignore any cases with "return;", technically this
// can be converted to "return undefined;" or some variant, but
// that does not help code size.
Node returnNode = IR.returnNode(