Updates:
Status: Assigned
Owner: [email protected]
Comment #1 on issue 1767 by [email protected]: numops-fuzz.js is
*very* slow when compiled with crankshaft in debug mode.
http://code.google.com/p/v8/issues/detail?id=1767
I've taken a look at what's going on there. The complexity of
HInstruction::Verify() is, in the worst case, quadratic in the number of
HInstructions per BasicBlock.
A proposed fix is at http://codereview.chromium.org/8302023; it doesn't
change the theoretical complexity, it just reverses the search direction,
applying the heuristic that the definition of a value will typically be
closer to its use than to the start of the block. This reduces the time
required to run the numops-fuzz test in debug mode by about 75%, and shaves
1-2% off the time required to run our entire test suite in debug mode.
Release mode is entirely unaffected as HInstruction::Verify() is behind
an "#ifdef DEBUG".
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