98 lines
3.8 KiB
C++
98 lines
3.8 KiB
C++
//===- llvm/Analysis/ScalarEvolutionDivision.h - See below ------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the class that knows how to divide SCEV's.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ANALYSIS_SCALAREVOLUTIONDIVISION_H
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#define LLVM_ANALYSIS_SCALAREVOLUTIONDIVISION_H
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#include "llvm/Analysis/ScalarEvolutionExpressions.h"
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namespace llvm {
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class SCEV;
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class ScalarEvolution;
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struct SCEVCouldNotCompute;
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struct SCEVDivision : public SCEVVisitor<SCEVDivision, void> {
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public:
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/// Computes the Quotient and Remainder of the division of Numerator by
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/// Denominator. We are not actually performing the division here. Instead, we
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/// are trying to find SCEV expressions Quotient and Remainder that satisfy:
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///
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/// Numerator = Denominator * Quotient + Remainder
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///
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/// There may be multiple valid answers for Quotient and Remainder. This
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/// function finds one of them. Especially, there is always a trivial
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/// solution: (Quotient, Remainder) = (0, Numerator).
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///
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/// Note the following:
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/// * The condition Remainder < Denominator is NOT necessarily required.
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/// * Division of constants is performed as signed.
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/// * The multiplication of Quotient and Denominator may wrap.
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/// * The addition of Quotient*Denominator and Remainder may wrap.
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LLVM_ABI static void divide(ScalarEvolution &SE, const SCEV *Numerator,
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const SCEV *Denominator, const SCEV **Quotient,
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const SCEV **Remainder);
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// Except in the trivial case described above, we do not know how to divide
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// Expr by Denominator for the following functions with empty implementation.
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void visitPtrToAddrExpr(const SCEVPtrToAddrExpr *Numerator) {}
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void visitPtrToIntExpr(const SCEVPtrToIntExpr *Numerator) {}
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void visitTruncateExpr(const SCEVTruncateExpr *Numerator) {}
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void visitZeroExtendExpr(const SCEVZeroExtendExpr *Numerator) {}
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void visitSignExtendExpr(const SCEVSignExtendExpr *Numerator) {}
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void visitUDivExpr(const SCEVUDivExpr *Numerator) {}
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void visitSMaxExpr(const SCEVSMaxExpr *Numerator) {}
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void visitUMaxExpr(const SCEVUMaxExpr *Numerator) {}
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void visitSMinExpr(const SCEVSMinExpr *Numerator) {}
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void visitUMinExpr(const SCEVUMinExpr *Numerator) {}
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void visitSequentialUMinExpr(const SCEVSequentialUMinExpr *Numerator) {}
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void visitUnknown(const SCEVUnknown *Numerator) {}
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void visitCouldNotCompute(const SCEVCouldNotCompute *Numerator) {}
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LLVM_ABI void visitConstant(const SCEVConstant *Numerator);
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LLVM_ABI void visitVScale(const SCEVVScale *Numerator);
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LLVM_ABI void visitAddRecExpr(const SCEVAddRecExpr *Numerator);
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LLVM_ABI void visitAddExpr(const SCEVAddExpr *Numerator);
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LLVM_ABI void visitMulExpr(const SCEVMulExpr *Numerator);
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private:
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SCEVDivision(ScalarEvolution &S, const SCEV *Numerator,
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const SCEV *Denominator);
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// Convenience function for giving up on the division. We set the quotient to
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// be equal to zero and the remainder to be equal to the numerator.
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void cannotDivide(const SCEV *Numerator);
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ScalarEvolution &SE;
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const SCEV *Denominator, *Quotient, *Remainder, *Zero, *One;
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};
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class SCEVDivisionPrinterPass
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: public RequiredPassInfoMixin<SCEVDivisionPrinterPass> {
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raw_ostream &OS;
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void runImpl(Function &F, ScalarEvolution &SE);
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public:
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explicit SCEVDivisionPrinterPass(raw_ostream &OS) : OS(OS) {}
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LLVM_ABI PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
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};
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} // end namespace llvm
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#endif // LLVM_ANALYSIS_SCALAREVOLUTIONDIVISION_H
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