mirror of
https://github.com/c64scene-ar/llvm-6502.git
synced 2024-12-22 23:31:32 +00:00
448db1cdef
explicitly split into stride-and-offset pairs. Also, add the ability to track multiple post-increment loops on the same expression. This refines the concept of "normalizing" SCEV expressions used for to post-increment uses, and introduces a dedicated utility routine for normalizing and denormalizing expressions. This fixes the expansion of expressions which are post-increment users of more than one loop at a time. More broadly, this takes LSR another step closer to being able to reason about more than one loop at a time. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@100699 91177308-0d34-0410-b5e6-96231b3b80d8
79 lines
2.7 KiB
C++
79 lines
2.7 KiB
C++
//===- llvm/Analysis/ScalarEvolutionNormalization.h - See below -*- C++ -*-===//
|
|
//
|
|
// The LLVM Compiler Infrastructure
|
|
//
|
|
// This file is distributed under the University of Illinois Open Source
|
|
// License. See LICENSE.TXT for details.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// 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_SCALAREVOLUTION_NORMALIZATION_H
|
|
#define LLVM_ANALYSIS_SCALAREVOLUTION_NORMALIZATION_H
|
|
|
|
#include "llvm/ADT/SmallPtrSet.h"
|
|
|
|
namespace llvm {
|
|
|
|
class Instruction;
|
|
class DominatorTree;
|
|
class Loop;
|
|
class ScalarEvolution;
|
|
class SCEV;
|
|
class Value;
|
|
|
|
/// TransformKind - Different types of transformations that
|
|
/// TransformForPostIncUse can do.
|
|
enum TransformKind {
|
|
/// Normalize - Normalize according to the given loops.
|
|
Normalize,
|
|
/// NormalizeAutodetect - Detect post-inc opportunities on new expressions,
|
|
/// update the given loop set, and normalize.
|
|
NormalizeAutodetect,
|
|
/// Denormalize - Perform the inverse transform on the expression with the
|
|
/// given loop set.
|
|
Denormalize
|
|
};
|
|
|
|
/// PostIncLoopSet - A set of loops.
|
|
typedef SmallPtrSet<const Loop *, 2> PostIncLoopSet;
|
|
|
|
/// TransformForPostIncUse - Transform the given expression according to the
|
|
/// given transformation kind.
|
|
const SCEV *TransformForPostIncUse(TransformKind Kind,
|
|
const SCEV *S,
|
|
Instruction *User,
|
|
Value *OperandValToReplace,
|
|
PostIncLoopSet &Loops,
|
|
ScalarEvolution &SE,
|
|
DominatorTree &DT);
|
|
|
|
}
|
|
|
|
#endif
|