Add 'umax' similar to 'smax' SCEV. Closes PR2003.

Parse reversed smax and umax as smin and umin and express them with negative
or binary-not SCEVs (which are really just subtract under the hood).

Parse 'xor %x, -1' as (-1 - %x).

Remove dead code (ConstantInt::get always returns a ConstantInt).

Don't use getIntegerSCEV(-1, Ty). The first value is an int, then it gets
passed into a uint64_t. Instead, create the -1 directly from
ConstantInt::getAllOnesValue().


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47360 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 35 insertions, 3 deletions

diff --git a/include/llvm/Analysis/ScalarEvolution.h b/include/llvm/Analysis/ScalarEvolution.h
index ecf28ad..4d9d5e5 100644
--- a/include/llvm/Analysis/ScalarEvolution.h
+++ b/include/llvm/Analysis/ScalarEvolution.h
@@ -237,12 +237,18 @@ namespace llvm {
     }
     SCEVHandle getSMaxExpr(const SCEVHandle &LHS, const SCEVHandle &RHS);
     SCEVHandle getSMaxExpr(std::vector<SCEVHandle> Operands);
+    SCEVHandle getUMaxExpr(const SCEVHandle &LHS, const SCEVHandle &RHS);
+    SCEVHandle getUMaxExpr(std::vector<SCEVHandle> Operands);
     SCEVHandle getUnknown(Value *V);
 
     /// getNegativeSCEV - Return the SCEV object corresponding to -V.
     ///
     SCEVHandle getNegativeSCEV(const SCEVHandle &V);
 
+    /// getNotSCEV - Return the SCEV object corresponding to ~V.
+    ///
+    SCEVHandle getNotSCEV(const SCEVHandle &V);
+
     /// getMinusSCEV - Return LHS-RHS.
     ///
     SCEVHandle getMinusSCEV(const SCEVHandle &LHS,
diff --git a/include/llvm/Analysis/ScalarEvolutionExpander.h b/include/llvm/Analysis/ScalarEvolutionExpander.h
index 530ce37..584e488 100644
--- a/include/llvm/Analysis/ScalarEvolutionExpander.h
+++ b/include/llvm/Analysis/ScalarEvolutionExpander.h
@@ -136,6 +136,8 @@ namespace llvm {
 
     Value *visitSMaxExpr(SCEVSMaxExpr *S);
 
+    Value *visitUMaxExpr(SCEVUMaxExpr *S);
+
     Value *visitUnknown(SCEVUnknown *S) {
       return S->getValue();
     }
diff --git a/include/llvm/Analysis/ScalarEvolutionExpressions.h b/include/llvm/Analysis/ScalarEvolutionExpressions.h
index 409ad9e..905493a 100644
--- a/include/llvm/Analysis/ScalarEvolutionExpressions.h
+++ b/include/llvm/Analysis/ScalarEvolutionExpressions.h
@@ -25,7 +25,8 @@ namespace llvm {
     // These should be ordered in terms of increasing complexity to make the
     // folders simpler.
     scConstant, scTruncate, scZeroExtend, scSignExtend, scAddExpr, scMulExpr,
-    scUDivExpr, scAddRecExpr, scSMaxExpr, scUnknown, scCouldNotCompute
+    scUDivExpr, scAddRecExpr, scUMaxExpr, scSMaxExpr, scUnknown,
+    scCouldNotCompute
   };
 
   //===--------------------------------------------------------------------===//
@@ -275,7 +276,8 @@ namespace llvm {
     static inline bool classof(const SCEV *S) {
       return S->getSCEVType() == scAddExpr ||
              S->getSCEVType() == scMulExpr ||
-             S->getSCEVType() == scSMaxExpr;
+             S->getSCEVType() == scSMaxExpr ||
+             S->getSCEVType() == scUMaxExpr;
     }
   };
 
@@ -483,6 +485,27 @@ namespace llvm {
 
 
   //===--------------------------------------------------------------------===//
+  /// SCEVUMaxExpr - This class represents an unsigned maximum selection.
+  ///
+  class SCEVUMaxExpr : public SCEVCommutativeExpr {
+    friend class ScalarEvolution;
+
+    explicit SCEVUMaxExpr(const std::vector<SCEVHandle> &ops)
+      : SCEVCommutativeExpr(scUMaxExpr, ops) {
+    }
+
+  public:
+    virtual const char *getOperationStr() const { return " umax "; }
+
+    /// Methods for support type inquiry through isa, cast, and dyn_cast:
+    static inline bool classof(const SCEVUMaxExpr *S) { return true; }
+    static inline bool classof(const SCEV *S) {
+      return S->getSCEVType() == scUMaxExpr;
+    }
+  };
+
+
+  //===--------------------------------------------------------------------===//
   /// SCEVUnknown - This means that we are dealing with an entirely unknown SCEV
   /// value, and only represent it as it's LLVM Value.  This is the "bottom"
   /// value for the analysis.
@@ -546,6 +569,8 @@ namespace llvm {
         return ((SC*)this)->visitAddRecExpr((SCEVAddRecExpr*)S);
       case scSMaxExpr:
         return ((SC*)this)->visitSMaxExpr((SCEVSMaxExpr*)S);
+      case scUMaxExpr:
+        return ((SC*)this)->visitUMaxExpr((SCEVUMaxExpr*)S);
       case scUnknown:
         return ((SC*)this)->visitUnknown((SCEVUnknown*)S);
       case scCouldNotCompute:
@@ -565,4 +590,3 @@ namespace llvm {
 }
 
 #endif
-