Turns out the SIM function is still available in R2014a. The issue was actually unrelated to the SIM function but rather to a bug in the Matlab Compiler as below:
32-bit compiled components generated with mcc and deploytool from MATLAB R2014a fail with 'undefined function' during runtime Description
On Windows, when using 32-bit MATLAB R2014a to deploy MATLAB code using mcc or deploytool, the deployed component fails during runtime with the 'undefined function' error.
This occurs because 32-bit MATLAB is most often installed into the 'C:\Program Files (x86)' directory, and the parentheses in the path name cause some functions to be missing in the generated component.