1 //===- llvm/Analysis/ScalarEvolutionDivision.h - See below ------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file defines the class that knows how to divide SCEV's.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #ifndef LLVM_ANALYSIS_SCALAREVOLUTIONDIVISION_H
14 #define LLVM_ANALYSIS_SCALAREVOLUTIONDIVISION_H
15 
16 #include "llvm/Analysis/ScalarEvolutionExpressions.h"
17 
18 namespace llvm {
19 
20 class SCEV;
21 
22 class ScalarEvolution;
23 
24 struct SCEVCouldNotCompute;
25 
26 struct SCEVDivision : public SCEVVisitor<SCEVDivision, void> {
27 public:
28   // Computes the Quotient and Remainder of the division of Numerator by
29   // Denominator.
30   static void divide(ScalarEvolution &SE, const SCEV *Numerator,
31                      const SCEV *Denominator, const SCEV **Quotient,
32                      const SCEV **Remainder);
33 
34   // Except in the trivial case described above, we do not know how to divide
35   // Expr by Denominator for the following functions with empty implementation.
visitPtrToIntExprSCEVDivision36   void visitPtrToIntExpr(const SCEVPtrToIntExpr *Numerator) {}
visitTruncateExprSCEVDivision37   void visitTruncateExpr(const SCEVTruncateExpr *Numerator) {}
visitZeroExtendExprSCEVDivision38   void visitZeroExtendExpr(const SCEVZeroExtendExpr *Numerator) {}
visitSignExtendExprSCEVDivision39   void visitSignExtendExpr(const SCEVSignExtendExpr *Numerator) {}
visitUDivExprSCEVDivision40   void visitUDivExpr(const SCEVUDivExpr *Numerator) {}
visitSMaxExprSCEVDivision41   void visitSMaxExpr(const SCEVSMaxExpr *Numerator) {}
visitUMaxExprSCEVDivision42   void visitUMaxExpr(const SCEVUMaxExpr *Numerator) {}
visitSMinExprSCEVDivision43   void visitSMinExpr(const SCEVSMinExpr *Numerator) {}
visitUMinExprSCEVDivision44   void visitUMinExpr(const SCEVUMinExpr *Numerator) {}
visitSequentialUMinExprSCEVDivision45   void visitSequentialUMinExpr(const SCEVSequentialUMinExpr *Numerator) {}
visitUnknownSCEVDivision46   void visitUnknown(const SCEVUnknown *Numerator) {}
visitCouldNotComputeSCEVDivision47   void visitCouldNotCompute(const SCEVCouldNotCompute *Numerator) {}
48 
49   void visitConstant(const SCEVConstant *Numerator);
50 
51   void visitVScale(const SCEVVScale *Numerator);
52 
53   void visitAddRecExpr(const SCEVAddRecExpr *Numerator);
54 
55   void visitAddExpr(const SCEVAddExpr *Numerator);
56 
57   void visitMulExpr(const SCEVMulExpr *Numerator);
58 
59 private:
60   SCEVDivision(ScalarEvolution &S, const SCEV *Numerator,
61                const SCEV *Denominator);
62 
63   // Convenience function for giving up on the division. We set the quotient to
64   // be equal to zero and the remainder to be equal to the numerator.
65   void cannotDivide(const SCEV *Numerator);
66 
67   ScalarEvolution &SE;
68   const SCEV *Denominator, *Quotient, *Remainder, *Zero, *One;
69 };
70 
71 } // end namespace llvm
72 
73 #endif // LLVM_ANALYSIS_SCALAREVOLUTIONDIVISION_H
74