Old house Fill gap between woodfloor and wall

[homeimprovementNube]

What material should I use to fill gap between the woodfloor and wall? My home had some foundation issues that has since been remediated but now there is a 3/4 inch gap between my wood floor and the wall. I plan on covering it with a shoe molding but I need to also fill that gap. What is the ideal/standard material I should use to fill this gap? Sheetrock? Wood fill? water putty?

[Timplex]

Cant you cut a piece of pine to that size and nail it in place?
That should work best in my opinion.