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Re: [Bug tree-optimization/15524] [4.0 Regression] jump threading on trees is slow with switch statements with large # of cases



On Nov 3, 2004, at 10:03 AM, Jeffrey A Law wrote:



With loop bounds recording no longer charged to the expander it's time to deal with the inefficiencies which are in the switch expander.

Basically we have code which does

for each case
  for each case
    see if the label in the outer loop matches any of the cases in the
    inner loop (up to the current case in the outer loop).

We don't really need some of this code anyways because the gimplifier now reorders the case statements so that you don't have to do the loop at all.

Thanks,
Andrew Pinski


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