[llvm] r306006 - [DAG] Add Target Store Merge pass ordering function

[Nirav Dave via llvm-commits]

Author: niravd
Date: Thu Jun 22 10:07:49 2017
New Revision: 306006

URL: http://llvm.org/viewvc/llvm-project?rev=306006&view=rev
Log:
[DAG] Add Target Store Merge pass ordering function

Allow targets to specify if they should merge stores before or after
legalization.

Modified:
    llvm/trunk/include/llvm/Target/TargetLowering.h
    llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

Modified: llvm/trunk/include/llvm/Target/TargetLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetLowering.h?rev=306006&r1=306005&r2=306006&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Target/TargetLowering.h (original)
+++ llvm/trunk/include/llvm/Target/TargetLowering.h Thu Jun 22 10:07:49 2017
@@ -410,6 +410,10 @@ public:
     return false;
   }
 
+  /// Should we merge stores after Legalization (generally
+  /// better quality) or before (simpler)
+  virtual bool mergeStoresAfterLegalization() const { return false; }
+
   /// Returns if it's reasonable to merge stores to MemVT size.
   virtual bool canMergeStoresTo(unsigned AddressSpace, EVT MemVT) const {
     return true;

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=306006&r1=306005&r2=306006&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Thu Jun 22 10:07:49 2017
@@ -13209,7 +13209,8 @@ SDValue DAGCombiner::visitSTORE(SDNode *
 
   // Only perform this optimization before the types are legal, because we
   // don't want to perform this optimization on every DAGCombine invocation.
-  if (!LegalTypes) {
+  if ((TLI.mergeStoresAfterLegalization()) ? Level == AfterLegalizeDAG
+                                           : !LegalTypes) {
     for (;;) {
       // There can be multiple store sequences on the same chain.
       // Keep trying to merge store sequences until we are unable to do so