[PATCH] D14688: [Polly] Introduce origin/kind for exit PHI node accesses

[Michael Kruse via llvm-commits]

Meinersbur updated the summary for this revision.
Meinersbur updated this revision to Diff 40316.
Meinersbur added a comment.

Grammar corrections. Thanks Tobias for the hints.


http://reviews.llvm.org/D14688

Files:
  include/polly/ScopInfo.h
  lib/Analysis/ScopInfo.cpp
  lib/CodeGen/BlockGenerators.cpp

Index: lib/CodeGen/BlockGenerators.cpp
===================================================================
--- lib/CodeGen/BlockGenerators.cpp
+++ lib/CodeGen/BlockGenerators.cpp
@@ -1201,7 +1201,7 @@
     ValueMapT *LocalBBMap = &BBMap;
 
     // Implicit writes induced by PHIs must be written in the incoming blocks.
-    if (isa<TerminatorInst>(ScalarInst)) {
+    if (MA->isPHI() || MA->isExitPHI()) {
       BasicBlock *ExitingBB = ScalarInst->getParent();
       BasicBlock *ExitingBBCopy = BlockMap[ExitingBB];
       Builder.SetInsertPoint(ExitingBBCopy->getTerminator());
@@ -1217,7 +1217,7 @@
     Builder.CreateStore(Val, Address);
 
     // Restore the insertion point if necessary.
-    if (isa<TerminatorInst>(ScalarInst))
+    if (MA->isPHI() || MA->isExitPHI())
       Builder.SetInsertPoint(SavedInsertBB, SavedInsertionPoint);
   }
 }
Index: lib/Analysis/ScopInfo.cpp
===================================================================
--- lib/Analysis/ScopInfo.cpp
+++ lib/Analysis/ScopInfo.cpp
@@ -876,6 +876,8 @@
     ScopArrayInfo::ARRAYKIND Ty;
     if (Access->isPHI())
       Ty = ScopArrayInfo::KIND_PHI;
+    else if (Access->isExitPHI())
+      Ty = ScopArrayInfo::KIND_EXIT_PHI;
     else if (Access->isImplicit())
       Ty = ScopArrayInfo::KIND_SCALAR;
     else
@@ -3855,7 +3857,7 @@
   addMemoryAccess(IncomingBlock, IncomingBlock->getTerminator(),
                   MemoryAccess::MUST_WRITE, PHI, 1, true, IncomingValue,
                   ArrayRef<const SCEV *>(), ArrayRef<const SCEV *>(),
-                  IsExitBlock ? MemoryAccess::SCALAR : MemoryAccess::PHI);
+                  IsExitBlock ? MemoryAccess::EXIT_PHI : MemoryAccess::PHI);
 }
 void ScopInfo::addPHIReadAccess(PHINode *PHI) {
   addMemoryAccess(PHI->getParent(), PHI, MemoryAccess::READ, PHI, 1, true, PHI,
Index: include/polly/ScopInfo.h
===================================================================
--- include/polly/ScopInfo.h
+++ include/polly/ScopInfo.h
@@ -105,6 +105,10 @@
     // Scalar references used to model PHI nodes
     KIND_PHI,
 
+    // Like KIND_PHI, but for PHIs in the exit node. Depending on context, these
+    // are handled like KIND_SCALAR.
+    KIND_EXIT_PHI,
+
     // References to (multi-dimensional) arrays
     KIND_ARRAY,
   };
@@ -324,7 +328,7 @@
   /// #AccessValue is also the llvm::Value itself.
   ///
   ///
-  /// * Accesses to emulate PHI nodes
+  /// * Accesses to emulate PHI nodes within the SCoP
   ///
   /// PHIInst instructions such as
   ///
@@ -359,7 +363,15 @@
   /// Note that there can also be a scalar write access for %PHI if used in a
   /// different BasicBlock, i.e. there can be a %PHI.phiops as well as a
   /// %PHI.s2a.
-  enum AccessOrigin { EXPLICIT, SCALAR, PHI };
+  ///
+  ///
+  /// * Accesses to emulate PHI nodes that are in the SCoP's exit block
+  ///
+  /// Like the previous, but the PHI itself is not located in the SCoP itself.
+  /// There will be no READ type MemoryAccess for such values. The PHINode's
+  /// llvm::Value is treated as a value escaping the SCoP. WRITE accesses write
+  /// directly to the escaping value's ".s2a" alloca.
+  enum AccessOrigin { EXPLICIT, SCALAR, PHI, EXIT_PHI };
 
   /// @brief The access type of a memory access
   ///
@@ -671,6 +683,10 @@
   /// @brief Is this MemoryAccess modeling special PHI node accesses?
   bool isPHI() const { return Origin == PHI; }
 
+  /// @brief Is this MemoryAccess modeling the accesses of a PHI node in the
+  /// SCoP's exit block?
+  bool isExitPHI() const { return Origin == EXIT_PHI; }
+
   /// @brief Get the statement that contains this memory access.
   ScopStmt *getStatement() const { return Statement; }
 


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