Jonas Paulsson 72374d2610 [ScheduleDAGInstrs::buildSchedGraph()] Handling of memory dependecies rewritten. ... The buildSchedGraph() was in need of reworking as the AA features had been added on top of earlier code. It was very difficult to understand, and buggy. There had been found cases where scheduling dependencies had actually been missed (see r228686). AliasChain, RejectMemNodes, adjustChainDeps() and iterateChainSucc() have been removed. There are instead now just the four maps from Value to SUs, which have been renamed to Stores, Loads, NonAliasStores and NonAliasLoads. An unknown store used to become the AliasChain, but now becomes a store mapped to 'unknownValue' (in Stores). What used to be PendingLoads is instead the list of SUs mapped to 'unknownValue' in Loads. RejectMemNodes and adjustChainDeps() used to be a safety-net for everything. The SU maps were sometimes cleared and SUs were put in RejectMemNodes, where adjustChainDeps() would look. Instead of this, a more straight forward approach is used in maintaining the SU maps without clearing them and simply letting them grow over time. Instead of the cutt-off in adjustChainDeps() search, a reduction of maps will be done if needed (see below). Each SUnit either becomes the BarrierChain, or is put into one of the maps. For each SUnit encountered, all the information about previous ones are still available until a new BarrierChain is set, at which point the maps are cleared. For huge regions, the algorithm becomes slow, therefore the maps will get reduced at a threshold (current default is 1000 nodes), by a fraction (default 1/2). These values can be tuned by use of CL options in case some test case shows that they need to be changed (-dag-maps-huge-region and -dag-maps-reduction-size). There has not been any considerable change observed in output quality or compile time. There may now be more DAG edges inserted than before (i.e. if A->B->C, then A->C is not needed). However, in a comparison run there were fewer total calls to AA, and a somewhat improved compile time, which means this seems to be not a problem. http://reviews.llvm.org/D8705 Reviewers: Hal Finkel, Andy Trick. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259201 91177308-0d34-0410-b5e6-96231b3b80d8		2016-01-29 16:11:18 +00:00
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llvm	[ScheduleDAGInstrs::buildSchedGraph()] Handling of memory dependecies rewritten.	2016-01-29 16:11:18 +00:00
llvm-c	Make some headers self-contained, remove unused includes that violate layering.	2016-01-27 16:05:37 +00:00