Use instruction itinerary to determine what instructions are 'cheap'.

[oota-llvm.git] / include / llvm / Analysis / ValueTracking.h

diff --git a/include/llvm/Analysis/ValueTracking.h b/include/llvm/Analysis/ValueTracking.h
index fa46921b593d67daa0b527e55bde6af29e10be79..7b6026fea0a60d0a8c643195514c30e957654e2e 100644 (file)
--- a/include/llvm/Analysis/ValueTracking.h
+++ b/include/llvm/Analysis/ValueTracking.h
@@ -15,29 +15,41 @@
 #ifndef LLVM_ANALYSIS_VALUETRACKING_H
 #define LLVM_ANALYSIS_VALUETRACKING_H
 
-#include "llvm/Support/DataTypes.h"
+#include "llvm/System/DataTypes.h"
 #include <string>
 
 namespace llvm {
+  template <typename T> class SmallVectorImpl;
   class Value;
   class Instruction;
   class APInt;
   class TargetData;
-  struct LLVMContext;
   
   /// ComputeMaskedBits - Determine which of the bits specified in Mask are
   /// known to be either zero or one and return them in the KnownZero/KnownOne
   /// bit sets.  This code only analyzes bits in Mask, in order to short-circuit
   /// processing.
+  ///
+  /// This function is defined on values with integer type, values with pointer
+  /// type (but only if TD is non-null), and vectors of integers.  In the case
+  /// where V is a vector, the mask, known zero, and known one values are the
+  /// same width as the vector element, and the bit is set only if it is true
+  /// for all of the elements in the vector.
   void ComputeMaskedBits(Value *V, const APInt &Mask, APInt &KnownZero,
-                         APInt &KnownOne, TargetData *TD = 0,
+                         APInt &KnownOne, const TargetData *TD = 0,
                          unsigned Depth = 0);
   
   /// MaskedValueIsZero - Return true if 'V & Mask' is known to be zero.  We use
   /// this predicate to simplify operations downstream.  Mask is known to be
   /// zero for bits that V cannot have.
+  ///
+  /// This function is defined on values with integer type, values with pointer
+  /// type (but only if TD is non-null), and vectors of integers.  In the case
+  /// where V is a vector, the mask, known zero, and known one values are the
+  /// same width as the vector element, and the bit is set only if it is true
+  /// for all of the elements in the vector.
   bool MaskedValueIsZero(Value *V, const APInt &Mask, 
-                         TargetData *TD = 0, unsigned Depth = 0);
+                         const TargetData *TD = 0, unsigned Depth = 0);
 
   
   /// ComputeNumSignBits - Return the number of times the sign bit of the
@@ -48,15 +60,25 @@ namespace llvm {
   ///
   /// 'Op' must have a scalar integer type.
   ///
-  unsigned ComputeNumSignBits(Value *Op, TargetData *TD = 0,
+  unsigned ComputeNumSignBits(Value *Op, const TargetData *TD = 0,
                               unsigned Depth = 0);
 
+  /// ComputeMultiple - This function computes the integer multiple of Base that
+  /// equals V.  If successful, it returns true and returns the multiple in
+  /// Multiple.  If unsuccessful, it returns false.  Also, if V can be
+  /// simplified to an integer, then the simplified V is returned in Val.  Look
+  /// through sext only if LookThroughSExt=true.
+  bool ComputeMultiple(Value *V, unsigned Base, Value *&Multiple,
+                       bool LookThroughSExt = false,
+                       unsigned Depth = 0);
+
   /// CannotBeNegativeZero - Return true if we can prove that the specified FP 
   /// value is never equal to -0.0.
   ///
   bool CannotBeNegativeZero(const Value *V, unsigned Depth = 0);
 
-  /// FindScalarValue - Given an aggregrate and an sequence of indices, see if
+  
+  /// FindInsertedValue - Given an aggregrate and an sequence of indices, see if
   /// the scalar value indexed is already around as a register, for example if
   /// it were inserted directly into the aggregrate.
   ///
@@ -65,16 +87,14 @@ namespace llvm {
   Value *FindInsertedValue(Value *V,
                            const unsigned *idx_begin,
                            const unsigned *idx_end,
-                           LLVMContext &Context,
                            Instruction *InsertBefore = 0);
 
   /// This is a convenience wrapper for finding values indexed by a single index
   /// only.
   inline Value *FindInsertedValue(Value *V, const unsigned Idx,
-                                  LLVMContext &Context,
                                   Instruction *InsertBefore = 0) {
     const unsigned Idxs[1] = { Idx };
-    return FindInsertedValue(V, &Idxs[0], &Idxs[1], Context, InsertBefore);
+    return FindInsertedValue(V, &Idxs[0], &Idxs[1], InsertBefore);
   }
   
   /// GetConstantStringInfo - This function computes the length of a
@@ -83,8 +103,13 @@ namespace llvm {
   /// StopAtNul is set to true (the default), the returned string is truncated
   /// by a nul character in the global.  If StopAtNul is false, the nul
   /// character is included in the result string.
-  bool GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset = 0,
+  bool GetConstantStringInfo(const Value *V, std::string &Str,
+                             uint64_t Offset = 0,
                              bool StopAtNul = true);
+                        
+  /// GetStringLength - If we can compute the length of the string pointed to by
+  /// the specified pointer, return 'len+1'.  If we can't, return 0.
+  uint64_t GetStringLength(Value *V);
 } // end namespace llvm
 
 #endif