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Re: Puzzle about CFG on rtl during delay slot schedule

On 04/02/10 05:26, Steven Bosscher wrote: 

Yes. The CFG is constructed on GIMPLE and then maintained all the way
through to reorg.c (or actually pass_free_cfg). Once destroyed, we
cannot resurrect the CFG.

In a perfect world, reorg.c would get a rewrite and we'd maintain the
CFG all the way through to final. But in practice, reorg.c is not the
only problem (for example, var-tracking also destroys the CFG, as do
most machine reorgs).
And that rewrite would use standard, well known & understood dependence analysis. reorg's methods for determine what insns can go into delay slots is utterly insane and can get extremely expensive.

jeff

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