You have a few options here. The first thing is that a query like this maybe impacted by bad parameter sniffing so test it with and without recompile.

1. Set @value = nullif(@value,'ALL') ... Location = coalesce(@value,Location) -- This should have at least statement level recompile

2. Dynamic SQL if @value <> 'ALL' set @whereStmt = N' where Location = @value '

There are a lot of different options actually, but I would consider the first two and see how performance is afterwards.