[DAGCombiner] Add an option to control whether or not to enable store merging.

Add an option to control whether or not to enable store merging in dag combiner
so we can workaround some bugs more easily.

Differential Revision: https://reviews.llvm.org/D65482

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@367365 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 835425021dcb30595b8914b9c929b036ac116591..bf62aa865098c644c44fab20a55b9f4a5f12a230 100644 (file)
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -111,6 +111,11 @@ static cl::opt<bool>
   MaySplitLoadIndex("combiner-split-load-index", cl::Hidden, cl::init(true),
                     cl::desc("DAG combiner may split indexing from loads"));
 
+static cl::opt<bool>
+    EnableStoreMerging("combiner-store-merging", cl::Hidden, cl::init(true),
+                       cl::desc("DAG combiner enable merging multiple stores "
+                                "into a wider store"));
+
 static cl::opt<unsigned> TokenFactorInlineLimit(
     "combiner-tokenfactor-inline-limit", cl::Hidden, cl::init(2048),
     cl::desc("Limit the number of operands to inline for Token Factors"));
@@ -15521,7 +15526,7 @@ bool DAGCombiner::checkMergeStoreCandidatesForDependencies(
 }
 
 bool DAGCombiner::MergeConsecutiveStores(StoreSDNode *St) {
-  if (OptLevel == CodeGenOpt::None)
+  if (OptLevel == CodeGenOpt::None || !EnableStoreMerging)
     return false;
 
   EVT MemVT = St->getMemoryVT();