As with any legal query, more specifics will be needed.  Speaking in the most general of senses, I think that the Patriot Act does not necessarily seek to embrace warrantless searches.  The Patriot Act simply widens the potential for searches that government officials deem as necessary in fighting enemy combatants or a clear threat of terror.  I am not entirely certain that the Patriot Act can be used to simply "go into" any person's home and search it without a warrant or probable cause.  Even the most ardent supporters of the Patriot Act will argue that some probable cause is needed.  At the same time, federal courts have sought to limit the scope of the Patriot Act with regards to searches without warrants.  Federal judges have tended to see the relevance of the original intent of the 4th Amendment in countering the Patriot Act provisions:

"It is critical that we, as a democratic nation, pay close attention to traditional Fourth Amendment principles," wrote Judge Ann Aiken of the U.S. District Court for the District of Oregon in her 44-page decision. "The Fourth Amendment has served this nation well for 220 years, through many other perils."

Even the most favorable readings of the Act would have to find some grounding in probable cause and basis for executing a search.  Without knowing the full details as to why the police officer would search any premises, I would suggest that this is where focus should lie.  Outside of this, I think that there is federal judicial precedent that indicates that warrantless searches are not deemed as Constitutional.