[llvm-commits] [llvm] r73360 - /llvm/trunk/include/llvm/Analysis/ScalarEvolution.h

[Dan Gohman]

Author: djg
Date: Sun Jun 14 17:55:07 2009
New Revision: 73360

URL: http://llvm.org/viewvc/llvm-project?rev=73360&view=rev
Log:
Specialize DenseMapInfo for SCEVHandle, so that SCEVHandles can be
used as keys in DenseMaps.

Modified:
    llvm/trunk/include/llvm/Analysis/ScalarEvolution.h

Modified: llvm/trunk/include/llvm/Analysis/ScalarEvolution.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Analysis/ScalarEvolution.h?rev=73360&r1=73359&r2=73360&view=diff

==============================================================================
--- llvm/trunk/include/llvm/Analysis/ScalarEvolution.h (original)
+++ llvm/trunk/include/llvm/Analysis/ScalarEvolution.h Sun Jun 14 17:55:07 2009
@@ -25,6 +25,7 @@
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/ValueHandle.h"
+#include "llvm/ADT/DenseMap.h"
 #include <iosfwd>
 
 namespace llvm {
@@ -34,6 +35,7 @@
   class SCEVHandle;
   class ScalarEvolution;
   class TargetData;
+  template<> struct DenseMapInfo<SCEVHandle>;
 
   /// SCEV - This class represents an analyzed expression in the program.  These
   /// are reference-counted opaque objects that the client is not allowed to
@@ -44,6 +46,7 @@
     mutable unsigned RefCount;
 
     friend class SCEVHandle;
+    friend class DenseMapInfo<SCEVHandle>;
     void addRef() const { ++RefCount; }
     void dropRef() const {
       if (--RefCount == 0)
@@ -197,6 +200,31 @@
   template<> struct simplify_type<SCEVHandle>
     : public simplify_type<const SCEVHandle> {};
 
+  // Specialize DenseMapInfo for SCEVHandle so that SCEVHandle may be used
+  // as a key in DenseMaps.
+  template<>
+  struct DenseMapInfo<SCEVHandle> {
+    static inline SCEVHandle getEmptyKey() {
+      static SCEVCouldNotCompute Empty;
+      if (Empty.RefCount == 0)
+        Empty.addRef();
+      return &Empty;
+    }
+    static inline SCEVHandle getTombstoneKey() {
+      static SCEVCouldNotCompute Tombstone;
+      if (Tombstone.RefCount == 0)
+        Tombstone.addRef();
+      return &Tombstone;
+    }
+    static unsigned getHashValue(const SCEVHandle &Val) {
+      return DenseMapInfo<const SCEV *>::getHashValue(Val);
+    }
+    static bool isEqual(const SCEVHandle &LHS, const SCEVHandle &RHS) {
+      return LHS == RHS;
+    }
+    static bool isPod() { return false; }
+  };
+
   /// ScalarEvolution - This class is the main scalar evolution driver.  Because
   /// client code (intentionally) can't do much with the SCEV objects directly,
   /// they must ask this class for services.