Hello, This brings down compile time for fwprop by avoiding CFG changes in loop_optimizer_init(). The CFG changes it could make would invalidate the fast dominance queries, so that walk_dominator_tree had to work with the slow queries -- rather painful on a CFG with an almost flat dominator tree.
With the n=10000 test case, we go from unpatched: forward prop : 39.13 (13%) usr to patched: forward prop : 13.60 ( 5%) usr That's still not a reasonable amount of time for such a simple pass, but it's better than before... To prevent that mistake in the future, I've add an assert in dominance.c. OK for trunk? Ciao! Steven
PR56113_3.diff
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