Simplicity Studio includes a free compiler (GCC), but printf() does not support floating point by default. This is to keep code size small. Floating point support can be achieved by the following procedure.
Select the project in the Project Explorer and right click → Property → C/C++ Build → Settings → Tool Settings → Gnu ARM C Linker → Miscellaneous. You can add/modify/delete from the Add, Delete, Edit icon on the right side of the screen. Add "-u_printf_float" here.