[ScopInfo] Introduce tryGetValueStored

Summary:
This makes code more readable and allows to reuse this functionality in
the future at other places.

Suggested-by Michael Kruse in post-commit review of r307660.

Reviewers: Meinersbur, bollu, gareevroman, efriedma, huihuiz, sebpop, simbuerg

Reviewed By: Meinersbur

Subscribers: pollydev, llvm-commits

Tags: #polly

Differential Revision: https://reviews.llvm.org/D35585

llvm-svn: 308435

2 files changed, 16 insertions, 7 deletions

diff --git a/polly/include/polly/ScopInfo.h b/polly/include/polly/ScopInfo.h
index 27f79ba..8089c54 100644
--- a/polly/include/polly/ScopInfo.h
+++ b/polly/include/polly/ScopInfo.h
@@ -889,6 +889,21 @@ public:
   /// Return the access value of this memory access.
   Value *getAccessValue() const { return AccessValue; }
 
+  /// Return llvm::Value that is stored by this access, if available.
+  ///
+  /// PHI nodes may not have a unique value available that is stored, as in
+  /// case of region statements one out of possibly several llvm::Values
+  /// might be stored. In this case nullptr is returned.
+  Value *tryGetValueStored() {
+    assert(isWrite() && "Only write statement store values");
+    if (isPHIKind()) {
+      if (Incoming.size() == 1)
+        return Incoming[0].second;
+      return nullptr;
+    }
+    return AccessValue;
+  }
+
   /// Return the access instruction of this memory access.
   Instruction *getAccessInstruction() const { return AccessInstruction; }
 
diff --git a/polly/lib/Transform/Simplify.cpp b/polly/lib/Transform/Simplify.cpp
index 8fbd353..1abffe1 100644
--- a/polly/lib/Transform/Simplify.cpp
+++ b/polly/lib/Transform/Simplify.cpp
@@ -238,13 +238,7 @@ private:
         if (!isa<StoreInst>(WA->getAccessInstruction()) && !WA->isPHIKind())
           continue;
 
-        auto ReadingValue = WA->getAccessValue();
-
-        if (WA->isPHIKind()) {
-          PHINode *PHI = cast<PHINode>(WA->getAccessValue());
-          BasicBlock *BB = Stmt.getBasicBlock();
-          ReadingValue = PHI->getIncomingValueForBlock(BB);
-        }
+        llvm::Value *ReadingValue = WA->tryGetValueStored();
 
         if (!ReadingValue)
           continue;