cost of Java "assert" when disabled?

[John Rose]

On Feb 16, 2012, at 1:59 PM, Vitaly Davidovich wrote:

> I think one problem with them is that they count towards the inlining budget since their bytecodes still take up space.  Not sure if newer C1/C2 compiler builds are "smarter" about this nowadays.

Optimized object code has (probably) no trace of the assertions themselves, but as Vitaly said, they perturb the inlining budget.  Larger methods have a tendency to "discourage" the inliner from inlining, causing more out-of-line calls and a rough net slowdown.  Currently, the non-executed bytecodes for assertions (which can be arbitrarily complex) make methods look bigger than they really are.  This is (IMO) a bug in the inlining heuristics, which should be fixed by examining inlining candidates with a little more care.  Since the escape analysis does a similar method summarization, there isn't necessarily even a need for an extra pass over the methods.

-- John
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