JuliaLang/julia — pull request #6644 by ArchRobison (2014-04-26 04:19:25+00:00)
Title: Speed up symbol lookup by using hash code has major key.

This pull request speeds up symbol lookup. It removes about 6% off the time to run ```julia runtests.jl linalg1``` for me. Here are times I measured:.

| | | | | | average | stdev
----------|--------|-------|-------|-------|-------|----------|------
original | 50.2 | 49.5 | 50.29 | 49.76 | 49.61 | 49.87 | 0.35
PR | 46.83 | 46.63 | 47.21 | 47.03 | 46.51 | 46.84 | 0.29

The change uses the hash code as the major sort key, which enables more comparisons to be done in a single word comparison instead of using ```strcmp```.

The PR also removes the need for an ifdef by replacing a constant with a formula that has the same value.