Enable merge by default for scalars

Signed-off-by: Mikhail R. Gadelha <[email protected]>

Author: mikhailramalho

llvm/include/llvm/CodeGen/TargetLowering.h

@@ -3508,7 +3508,7 @@ class TargetLoweringBase {
 
   /// Returns true if it's profitable to allow merging store of loads when there
   /// are functions calls between the load and the store.
-  virtual bool shouldMergeStoreOfLoadsOverCall() const { return true; }
+  virtual bool shouldMergeStoreOfLoadsOverCall(EVT) const { return true; }
 
   //===----------------------------------------------------------------------===//
   //  GlobalISel Hooks

llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

@@ -21417,7 +21417,8 @@ bool DAGCombiner::tryStoreMergeOfLoads(SmallVectorImpl<MemOpLink> &StoreNodes,
     }
 
     // Check if there is a call in the load/store chain.
-    if (!TLI.shouldMergeStoreOfLoadsOverCall() && HasCallInLdStChain(Ld, St)) {
+    if (!TLI.shouldMergeStoreOfLoadsOverCall(MemVT) &&
+        HasCallInLdStChain(Ld, St)) {
       StIt = StoreNodes.erase(StIt);
     } else {
       LoadNodes.push_back(MemOpLink(Ld, LdOffset));

llvm/lib/Target/RISCV/RISCVISelLowering.h

@@ -1070,10 +1070,11 @@ class RISCVTargetLowering : public TargetLowering {
     return false;
   }
 
-  /// Disables storing and loading vectors when there are function calls between
-  /// the load and store, since these are more expensive than just using scalars
-  bool shouldMergeStoreOfLoadsOverCall() const override {
-    return false;
+  /// Disables storing and loading vectors by default when there are function
+  /// calls between the load and store, since these are more expensive than just
+  /// using scalars
+  bool shouldMergeStoreOfLoadsOverCall(EVT VT) const override {
+    return VT.isScalarInteger();
   }
 
   /// For available scheduling models FDIV + two independent FMULs are much