From 35bda8914c0d1c02a6f90f42e7810c83150737e1 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sun, 6 Feb 2011 21:44:57 +0000
Subject: enhance vmcore to know that udiv's can be exact, and add a trivial
 instcombine xform to exercise this.

Nothing forms exact udivs yet though.  This is progress on PR8862



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124992 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Bitcode/LLVMBitCodes.h |  8 +++---
 include/llvm/Constants.h            |  1 +
 include/llvm/InstrTypes.h           |  2 +-
 include/llvm/Operator.h             | 53 ++++++++++++++++++++++++++++++-------
 4 files changed, 50 insertions(+), 14 deletions(-)

(limited to 'include')

diff --git a/include/llvm/Bitcode/LLVMBitCodes.h b/include/llvm/Bitcode/LLVMBitCodes.h
index d15c3ce93e..7692bd2872 100644
--- a/include/llvm/Bitcode/LLVMBitCodes.h
+++ b/include/llvm/Bitcode/LLVMBitCodes.h
@@ -199,10 +199,10 @@ namespace bitc {
     OBO_NO_SIGNED_WRAP = 1
   };
 
-  /// SDivOperatorOptionalFlags - Flags for serializing SDivOperator's
-  /// SubclassOptionalData contents.
-  enum SDivOperatorOptionalFlags {
-    SDIV_EXACT = 0
+  /// PossiblyExactOperatorOptionalFlags - Flags for serializing 
+  /// PossiblyExactOperator's SubclassOptionalData contents.
+  enum PossiblyExactOperatorOptionalFlags {
+    PEO_EXACT = 0
   };
 
   // The function body block (FUNCTION_BLOCK_ID) describes function bodies.  It
diff --git a/include/llvm/Constants.h b/include/llvm/Constants.h
index a7653948f1..b782737d31 100644
--- a/include/llvm/Constants.h
+++ b/include/llvm/Constants.h
@@ -725,6 +725,7 @@ public:
   static Constant *getNSWMul(Constant *C1, Constant *C2);
   static Constant *getNUWMul(Constant *C1, Constant *C2);
   static Constant *getExactSDiv(Constant *C1, Constant *C2);
+  static Constant *getExactUDiv(Constant *C1, Constant *C2);
 
   /// Transparently provide more efficient getOperand methods.
   DECLARE_TRANSPARENT_OPERAND_ACCESSORS(Constant);
diff --git a/include/llvm/InstrTypes.h b/include/llvm/InstrTypes.h
index 9dcf688358..1bb50b78fa 100644
--- a/include/llvm/InstrTypes.h
+++ b/include/llvm/InstrTypes.h
@@ -341,7 +341,7 @@ public:
     BO->setIsExact(true);
     return BO;
   }
-
+  
   /// Helper functions to construct and inspect unary operations (NEG and NOT)
   /// via binary operators SUB and XOR:
   ///
diff --git a/include/llvm/Operator.h b/include/llvm/Operator.h
index 3aae586f14..288edf1224 100644
--- a/include/llvm/Operator.h
+++ b/include/llvm/Operator.h
@@ -173,30 +173,47 @@ public:
   }
 };
 
-/// SDivOperator - An Operator with opcode Instruction::SDiv.
-///
-class SDivOperator : public Operator {
+/// PossiblyExactOperator - A udiv or sdiv instruction, which can be marked as
+/// "exact", indicating that no bits are destroyed.
+class PossiblyExactOperator : public Operator {
 public:
   enum {
     IsExact = (1 << 0)
   };
-
-private:
-  ~SDivOperator(); // do not implement
-
+  
   friend class BinaryOperator;
   friend class ConstantExpr;
   void setIsExact(bool B) {
     SubclassOptionalData = (SubclassOptionalData & ~IsExact) | (B * IsExact);
   }
-
+  
+private:
+  ~PossiblyExactOperator(); // do not implement
 public:
   /// isExact - Test whether this division is known to be exact, with
   /// zero remainder.
   bool isExact() const {
     return SubclassOptionalData & IsExact;
   }
-
+  
+  static inline bool classof(const ConstantExpr *CE) {
+    return CE->getOpcode() == Instruction::SDiv ||
+           CE->getOpcode() == Instruction::UDiv;
+  }
+  static inline bool classof(const Instruction *I) {
+    return I->getOpcode() == Instruction::SDiv ||
+           I->getOpcode() == Instruction::UDiv;
+  }
+  static inline bool classof(const Value *V) {
+    return (isa<Instruction>(V) && classof(cast<Instruction>(V))) ||
+    (isa<ConstantExpr>(V) && classof(cast<ConstantExpr>(V)));
+  }
+};
+  
+/// SDivOperator - An Operator with opcode Instruction::SDiv.
+///
+class SDivOperator : public PossiblyExactOperator {
+public:
   // Methods for support type inquiry through isa, cast, and dyn_cast:
   static inline bool classof(const SDivOperator *) { return true; }
   static inline bool classof(const ConstantExpr *CE) {
@@ -211,6 +228,24 @@ public:
   }
 };
 
+/// UDivOperator - An Operator with opcode Instruction::SDiv.
+///
+class UDivOperator : public PossiblyExactOperator {
+public:
+  // Methods for support type inquiry through isa, cast, and dyn_cast:
+  static inline bool classof(const UDivOperator *) { return true; }
+  static inline bool classof(const ConstantExpr *CE) {
+    return CE->getOpcode() == Instruction::UDiv;
+  }
+  static inline bool classof(const Instruction *I) {
+    return I->getOpcode() == Instruction::UDiv;
+  }
+  static inline bool classof(const Value *V) {
+    return (isa<Instruction>(V) && classof(cast<Instruction>(V))) ||
+    (isa<ConstantExpr>(V) && classof(cast<ConstantExpr>(V)));
+  }
+};
+  
 class GEPOperator : public Operator {
   enum {
     IsInBounds = (1 << 0)
-- 
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