I have a C application running on TI CC2650 SENSORTAG microcontroller that performs gesture recognition. Is there any way I can figure out its estimated power usage probably through Raspberry Pi or something, so that I can use it to compare the actual power consumed when I synthesize it on a FPGA? This is an academic project targetted at Hardware acceleration.
Your equivalent question is to measure the length of a plank without a measure.
You can always eyeball it. The Mic datasheet will provide the current consumption under various conditions, with different peripherals turned on. That's your best bet.
What you are trying to do won't really work. First a "C program" doesn't consume a particular amount of power.
A particular program performing a particular task on a particular processor may cause a reasonably measurable increase in power draw by that processor, or not. The power draw of a processor will only change significantly if it would otherwise go into some kind of low power mode if the "program" wasn't running. On many small systems, not doing one thing only means doing more of other things. The only effect of running a particular piece of code might be to respond with higher latency to new events, for example.
Even if you can measure a reasonably repeatable power increase in one processor due to running a particular program, that is little indication of anything useful for the same task performed some other way using different technology. You really should not expect the power increase due to a RPi running a particular program to have a meaningful correlation to the power required to run a FPGA that performs the same function.