llvm-6502/include/llvm/Analysis/Expressions.h
2002-08-30 22:53:53 +00:00

54 lines
1.8 KiB
C++

//===- llvm/Analysis/Expressions.h - Expression Analysis Utils ---*- C++ -*--=//
//
// This file defines a package of expression analysis utilties:
//
// ClassifyExpression: Analyze an expression to determine the complexity of the
// expression, and which other variables it depends on.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_EXPRESSIONS_H
#define LLVM_ANALYSIS_EXPRESSIONS_H
#include <assert.h>
class Type;
class Value;
class ConstantInt;
struct ExprType;
// ClassifyExpression: Analyze an expression to determine the complexity of the
// expression, and which other values it depends on.
//
ExprType ClassifyExpression(Value *Expr);
// ExprType - Represent an expression of the form CONST*VAR+CONST
// or simpler. The expression form that yields the least information about the
// expression is just the Linear form with no offset.
//
struct ExprType {
enum ExpressionType {
Constant, // Expr is a simple constant, Offset is value
Linear, // Expr is linear expr, Value is Var+Offset
ScaledLinear, // Expr is scaled linear exp, Value is Scale*Var+Offset
} ExprTy;
const ConstantInt *Offset; // Offset of expr, or null if 0
Value *Var; // Var referenced, if Linear or above (null if 0)
const ConstantInt *Scale; // Scale of var if ScaledLinear expr (null if 1)
inline ExprType(const ConstantInt *CPV = 0) {
Offset = CPV; Var = 0; Scale = 0;
ExprTy = Constant;
}
ExprType(Value *Val); // Create a linear or constant expression
ExprType(const ConstantInt *scale, Value *var, const ConstantInt *offset);
// If this expression has an intrinsic type, return it. If it is zero, return
// the specified type.
//
const Type *getExprType(const Type *Default) const;
};
#endif