O/R In company news, Canada's Ritchie Bros Auctioneers Inc RBA.TO said it had completed the acquisition of U.S. auto retailer IAA Inc IAA.N, weeks after two proxy advisory firms urged shareholders to reject the $7 billion deal. March 21 (Reuters) - Canada's main stock index was set to extend gains on Tuesday, tracking higher crude-oil prices, ahead of inflation data. Contracts tied to oil prices were in gains after the Credit Suisse rescue over the weekend eased global crude demand worries among investors.