llvm-6502/include/llvm/Analysis/ConstantFolding.h
Mehdi Amini 529919ff31 DataLayout is mandatory, update the API to reflect it with references.
Summary:
Now that the DataLayout is a mandatory part of the module, let's start
cleaning the codebase. This patch is a first attempt at doing that.

This patch is not exactly NFC as for instance some places were passing
a nullptr instead of the DataLayout, possibly just because there was a
default value on the DataLayout argument to many functions in the API.
Even though it is not purely NFC, there is no change in the
validation.

I turned as many pointer to DataLayout to references, this helped
figuring out all the places where a nullptr could come up.

I had initially a local version of this patch broken into over 30
independant, commits but some later commit were cleaning the API and
touching part of the code modified in the previous commits, so it
seemed cleaner without the intermediate state.

Test Plan:

Reviewers: echristo

Subscribers: llvm-commits

From: Mehdi Amini <mehdi.amini@apple.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231740 91177308-0d34-0410-b5e6-96231b3b80d8
2015-03-10 02:37:25 +00:00

103 lines
4.7 KiB
C++

//===-- ConstantFolding.h - Fold instructions into constants ----*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file declares routines for folding instructions into constants when all
// operands are constants, for example "sub i32 1, 0" -> "1".
//
// Also, to supplement the basic VMCore ConstantExpr simplifications,
// this file declares some additional folding routines that can make use of
// DataLayout information. These functions cannot go in VMCore due to library
// dependency issues.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_ANALYSIS_CONSTANTFOLDING_H
#define LLVM_ANALYSIS_CONSTANTFOLDING_H
namespace llvm {
class Constant;
class ConstantExpr;
class Instruction;
class DataLayout;
class TargetLibraryInfo;
class Function;
class Type;
template<typename T>
class ArrayRef;
/// ConstantFoldInstruction - Try to constant fold the specified instruction.
/// If successful, the constant result is returned, if not, null is returned.
/// Note that this fails if not all of the operands are constant. Otherwise,
/// this function can only fail when attempting to fold instructions like loads
/// and stores, which have no constant expression form.
Constant *ConstantFoldInstruction(Instruction *I, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr);
/// ConstantFoldConstantExpression - Attempt to fold the constant expression
/// using the specified DataLayout. If successful, the constant result is
/// result is returned, if not, null is returned.
Constant *
ConstantFoldConstantExpression(const ConstantExpr *CE, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr);
/// ConstantFoldInstOperands - Attempt to constant fold an instruction with the
/// specified operands. If successful, the constant result is returned, if not,
/// null is returned. Note that this function can fail when attempting to
/// fold instructions like loads and stores, which have no constant expression
/// form.
///
Constant *ConstantFoldInstOperands(unsigned Opcode, Type *DestTy,
ArrayRef<Constant *> Ops,
const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr);
/// ConstantFoldCompareInstOperands - Attempt to constant fold a compare
/// instruction (icmp/fcmp) with the specified operands. If it fails, it
/// returns a constant expression of the specified operands.
///
Constant *
ConstantFoldCompareInstOperands(unsigned Predicate, Constant *LHS,
Constant *RHS, const DataLayout &DL,
const TargetLibraryInfo *TLI = nullptr);
/// ConstantFoldInsertValueInstruction - Attempt to constant fold an insertvalue
/// instruction with the specified operands and indices. The constant result is
/// returned if successful; if not, null is returned.
Constant *ConstantFoldInsertValueInstruction(Constant *Agg, Constant *Val,
ArrayRef<unsigned> Idxs);
/// ConstantFoldLoadFromConstPtr - Return the value that a load from C would
/// produce if it is constant and determinable. If this is not determinable,
/// return null.
Constant *ConstantFoldLoadFromConstPtr(Constant *C, const DataLayout &DL);
/// ConstantFoldLoadThroughGEPConstantExpr - Given a constant and a
/// getelementptr constantexpr, return the constant value being addressed by the
/// constant expression, or null if something is funny and we can't decide.
Constant *ConstantFoldLoadThroughGEPConstantExpr(Constant *C, ConstantExpr *CE);
/// ConstantFoldLoadThroughGEPIndices - Given a constant and getelementptr
/// indices (with an *implied* zero pointer index that is not in the list),
/// return the constant value being addressed by a virtual load, or null if
/// something is funny and we can't decide.
Constant *ConstantFoldLoadThroughGEPIndices(Constant *C,
ArrayRef<Constant*> Indices);
/// canConstantFoldCallTo - Return true if its even possible to fold a call to
/// the specified function.
bool canConstantFoldCallTo(const Function *F);
/// ConstantFoldCall - Attempt to constant fold a call to the specified function
/// with the specified arguments, returning null if unsuccessful.
Constant *ConstantFoldCall(Function *F, ArrayRef<Constant *> Operands,
const TargetLibraryInfo *TLI = nullptr);
}
#endif