[PATCH] D18762: Rewrite Aggressive Dead Code Elimination

[David Callahan via llvm-commits]

david2050 added a comment.

I am sympathetic of course to the view of incremental changes but I don't really think it is effective in this case because so much functionality has to come online in one go.  There is a kernel this is common (propagating liveness as a sparse backwards flow problem, lines 488-497) but that is quite small.  The next logical step is to defer deleting branches until you know they control something live. This needs to be done in batches to use IDFCalculator efficiently and adds an outer loop. However, once you start having *any* dead control flow you need to deal with the complexities of phi nodes and the attendant problems with changing the control flow graph. There is not really any useful intermediate step,


http://reviews.llvm.org/D18762