3 files changed, 42 insertions, 6 deletions

diff --git a/polly/include/polly/ScopInfo.h b/polly/include/polly/ScopInfo.h
index fbaa5a83b59..32b61b70b52 100644
--- a/polly/include/polly/ScopInfo.h
+++ b/polly/include/polly/ScopInfo.h
@@ -1422,6 +1422,10 @@ public:
     return ValueReads.lookup(Inst);
   }
 
+  /// Return the MemoryAccess that loads a PHINode value, or nullptr if not
+  /// existing, respectively not yet added.
+  MemoryAccess *lookupPHIReadOf(PHINode *PHI) const;
+
   /// Return the PHI write MemoryAccess for the incoming values from any
   ///        basic block in this ScopStmt, or nullptr if not existing,
   ///        respectively not yet added.
@@ -1430,6 +1434,28 @@ public:
     return PHIWrites.lookup(PHI);
   }
 
+  /// Return the input access of the value, or null if no such MemoryAccess
+  /// exists.
+  ///
+  /// The input access is the MemoryAccess that makes an inter-statement value
+  /// available in this statement by reading it at the start of this statement.
+  /// This can be a MemoryKind::Value if defined in another statement or a
+  /// MemoryKind::PHI if the value is a PHINode in this statement.
+  MemoryAccess *lookupInputAccessOf(Value *Val) const {
+    if (isa<PHINode>(Val))
+      if (auto InputMA = lookupPHIReadOf(cast<PHINode>(Val))) {
+        assert(!lookupValueReadOf(Val) && "input accesses must be unique; a "
+                                          "statement cannot read a .s2a and "
+                                          ".phiops simultaneously");
+        return InputMA;
+      }
+
+    if (auto *InputMA = lookupValueReadOf(Val))
+      return InputMA;
+
+    return nullptr;
+  }
+
   /// Add @p Access to this statement's list of accesses.
   void addAccess(MemoryAccess *Access);
 
diff --git a/polly/lib/Analysis/ScopInfo.cpp b/polly/lib/Analysis/ScopInfo.cpp
index a5406100bf0..462ff6314f8 100644
--- a/polly/lib/Analysis/ScopInfo.cpp
+++ b/polly/lib/Analysis/ScopInfo.cpp
@@ -1285,6 +1285,19 @@ void ScopStmt::buildAccessRelations() {
   }
 }
 
+MemoryAccess *ScopStmt::lookupPHIReadOf(PHINode *PHI) const {
+  for (auto *MA : *this) {
+    if (!MA->isRead())
+      continue;
+    if (!MA->isLatestAnyPHIKind())
+      continue;
+
+    if (MA->getAccessInstruction() == PHI)
+      return MA;
+  }
+  return nullptr;
+}
+
 void ScopStmt::addAccess(MemoryAccess *Access) {
   Instruction *AccessInst = Access->getAccessInstruction();
 
diff --git a/polly/lib/Transform/DeLICM.cpp b/polly/lib/Transform/DeLICM.cpp
index 72abb088845..7bcb0726632 100644
--- a/polly/lib/Transform/DeLICM.cpp
+++ b/polly/lib/Transform/DeLICM.cpp
@@ -1949,12 +1949,9 @@ private:
       }
     };
 
-    // Add initial scalar. Either the value written by the store, or all inputs
-    // of its statement.
-    auto WrittenValUse = VirtualUse::create(
-        S, TargetStoreMA->getAccessInstruction()->getOperandUse(0), LI, true);
-    if (WrittenValUse.isInter())
-      Worklist.push_back(WrittenValUse.getMemoryAccess());
+    auto *WrittenVal = TargetStoreMA->getAccessInstruction()->getOperand(0);
+    if (auto *WrittenValInputMA = TargetStmt->lookupInputAccessOf(WrittenVal))
+      Worklist.push_back(WrittenValInputMA);
     else
       ProcessAllIncoming(TargetStmt);