[llvm-commits] [llvm] r161803 - in /llvm/trunk: include/llvm/Support/ValueHandle.h lib/Transforms/Utils/SSAUpdater.cpp

[Nadav Rotem]

Author: nadav
Date: Mon Aug 13 18:06:54 2012
New Revision: 161803

URL: http://llvm.org/viewvc/llvm-project?rev=161803&view=rev
Log:
LICM uses AliasSet information to hoist and sink instructions. However, other passes, such as LoopRotate
may invalidate its AliasSet because SSAUpdater does not update the AliasSet properly.
This patch teaches SSAUpdater to notify AliasSet that it made changes.
The testcase in PR12901 is too big to be useful and I could not reduce it to a normal size. 

rdar://11872059 PR12901


Modified:
    llvm/trunk/include/llvm/Support/ValueHandle.h
    llvm/trunk/lib/Transforms/Utils/SSAUpdater.cpp

Modified: llvm/trunk/include/llvm/Support/ValueHandle.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/ValueHandle.h?rev=161803&r1=161802&r2=161803&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/ValueHandle.h (original)
+++ llvm/trunk/include/llvm/Support/ValueHandle.h Mon Aug 13 18:06:54 2012
@@ -110,11 +110,12 @@
            V != DenseMapInfo<Value *>::getTombstoneKey();
   }
 
-private:
+public:
   // Callbacks made from Value.
   static void ValueIsDeleted(Value *V);
   static void ValueIsRAUWd(Value *Old, Value *New);
 
+private:
   // Internal implementation details.
   ValueHandleBase **getPrevPtr() const { return PrevPair.getPointer(); }
   HandleBaseKind getKind() const { return PrevPair.getInt(); }

Modified: llvm/trunk/lib/Transforms/Utils/SSAUpdater.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/SSAUpdater.cpp?rev=161803&r1=161802&r2=161803&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/SSAUpdater.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/SSAUpdater.cpp Mon Aug 13 18:06:54 2012
@@ -214,6 +214,11 @@
   else
     V = GetValueInMiddleOfBlock(User->getParent());
 
+  // Notify that users of the existing value that it is being replaced.
+  Value *OldVal = U.get();
+  if (OldVal != V && OldVal->hasValueHandle())
+    ValueHandleBase::ValueIsRAUWd(OldVal, V);
+
   U.set(V);
 }