Programmatic compiler optimization of glacial constants

Optimizations are programmatically applied by a compiler (preferably, a just-in-time or "JIT" compiler), and enable achieving improved performance while a variable acts as a global constant, yet also allow code to execute correctly if the global constant's run-time value changes from the value on which the optimization was originally based. Code snippets that dynamically patch executable code are described, where these code snippets take corrective actions to enable correct program execution following a run-time change to the value of a glacial constant. A backup recovery path may also be maintained, where this path provides code that is executed in the event of a change to a glacial constant and that treats the glacial constant as a variable. Recompilation may also be used after a change to a glacial constant, where the originally-compiled code has made an assumption about the glacial constant's value that is no longer accurate. Combinations of these approaches may be used.