Proplem with Code Composer Studio v6 with GCC
The driverlib in your case is compiled using the Floating Point Unit (FPU), while the target project does not. Try adding -mfloat-abi=hard -mfpu=fpv4-sp-d16 flags or recompiling driverlib without hardware FPU. In any case the FPU settings should be identical when compiling the library and the project. 
UPD:
If these flags do not work, the calling convention could be different. So you can try -mfloat-abi=soft -mfpu=fpv4-sp-d16 or -mfloat-abi=softfp -mfpu=fpv4-sp-d16 
UPD2:
 And yes, you might need to clean the project before recompiling.