How did this get modded up to "Informative"? This is misinformation. If you believe what an FPGA vendor tells you about their tools then I have some land in Florida you might be interested in. There is NO push button path from C to hardware, unless you consider compiling the C into object code that is burned into ROM as a hardware solution. Yes, there are tools like Cynthesizer from Forte and the cited tool from Xilinx that use C as an input language, but it is gerrymandered C geared toward synthesis, not "dusty deck" C.
As stated above, there are too many tradeoffs in time and space to provide a simple answer to your interested party. You should hire someone who can find a couple of points in the solution space and give your interested party an educated answer like "At xx mm^2 it runs this fast with this latency, while at yy mm^2 it runs this fast at this latency with 50% better power".