| //===- llvm/Analysis/ScalarEvolutionNormalization.h - See below -*- C++ -*-===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file defines utilities for working with "normalized" ScalarEvolution |
| // expressions. |
| // |
| // The following example illustrates post-increment uses and how normalized |
| // expressions help. |
| // |
| // for (i=0; i!=n; ++i) { |
| // ... |
| // } |
| // use(i); |
| // |
| // While the expression for most uses of i inside the loop is {0,+,1}<%L>, the |
| // expression for the use of i outside the loop is {1,+,1}<%L>, since i is |
| // incremented at the end of the loop body. This is inconveient, since it |
| // suggests that we need two different induction variables, one that starts |
| // at 0 and one that starts at 1. We'd prefer to be able to think of these as |
| // the same induction variable, with uses inside the loop using the |
| // "pre-incremented" value, and uses after the loop using the |
| // "post-incremented" value. |
| // |
| // Expressions for post-incremented uses are represented as an expression |
| // paired with a set of loops for which the expression is in "post-increment" |
| // mode (there may be multiple loops). |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_ANALYSIS_SCALAREVOLUTIONNORMALIZATION_H |
| #define LLVM_ANALYSIS_SCALAREVOLUTIONNORMALIZATION_H |
| |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/SmallPtrSet.h" |
| #include "llvm/Analysis/ScalarEvolutionExpressions.h" |
| |
| namespace llvm { |
| |
| class Loop; |
| class ScalarEvolution; |
| class SCEV; |
| |
| typedef SmallPtrSet<const Loop *, 2> PostIncLoopSet; |
| |
| typedef function_ref<bool(const SCEVAddRecExpr *)> NormalizePredTy; |
| |
| /// Normalize \p S to be post-increment for all loops present in \p |
| /// Loops. |
| const SCEV *normalizeForPostIncUse(const SCEV *S, const PostIncLoopSet &Loops, |
| ScalarEvolution &SE); |
| |
| /// Normalize \p S for all add recurrence sub-expressions for which \p |
| /// Pred returns true. |
| const SCEV *normalizeForPostIncUseIf(const SCEV *S, NormalizePredTy Pred, |
| ScalarEvolution &SE); |
| |
| /// Denormalize \p S to be post-increment for all loops present in \p |
| /// Loops. |
| const SCEV *denormalizeForPostIncUse(const SCEV *S, const PostIncLoopSet &Loops, |
| ScalarEvolution &SE); |
| } // namespace llvm |
| |
| #endif |