search for: d7181

...pile at /O0. I recently suggested a patch to disable one specific DAG combine at /O0 that broke stepping on a particular case (http://reviews.llvm.org/D19268), but other similar cases could appear. In the same way, another patch was submitted last year for a similar reason (http://reviews.llvm.org/D7181). So, since the DAGCombiner is in fact an optimization pass, could it be disabled completely (or partially?) in /O0? And how should it be done? For example, would this patch be too aggressive? Index: DAGCombiner.cpp =================================================================== --- DAGCombi...

...lISel. Cheers, -Quentin > On May 13, 2016, at 12:51 PM, Robinson, Paul via llvm-dev <llvm-dev at lists.llvm.org> wrote: > > (Remembering to re-add llvm-dev again…) > Yes, this would be too aggressive. DAG combiner does more than just optimization (which I discovered as part of D7181, see PR22346). > Internally we've thrown around other ideas, for example inside the worklist loop, skip loads and stores at O0, but haven't done any actual experiments. There are probably other bits of the combiner that could be turned off at O0, but I think they'd have to be consid...