1
//===-- ConstantFolding.h - Fold instructions into constants --------------===//
3
// The LLVM Compiler Infrastructure
5
// This file is distributed under the University of Illinois Open Source
6
// License. See LICENSE.TXT for details.
8
//===----------------------------------------------------------------------===//
10
// This file declares routines for folding instructions into constants.
12
// Also, to supplement the basic VMCore ConstantExpr simplifications,
13
// this file declares some additional folding routines that can make use of
14
// TargetData information. These functions cannot go in VMCore due to library
17
//===----------------------------------------------------------------------===//
19
#ifndef LLVM_ANALYSIS_CONSTANTFOLDING_H
20
#define LLVM_ANALYSIS_CONSTANTFOLDING_H
30
/// ConstantFoldInstruction - Attempt to constant fold the specified
31
/// instruction. If successful, the constant result is returned, if not, null
32
/// is returned. Note that this function can only fail when attempting to fold
33
/// instructions like loads and stores, which have no constant expression form.
35
Constant *ConstantFoldInstruction(Instruction *I, const TargetData *TD = 0);
37
/// ConstantFoldConstantExpression - Attempt to fold the constant expression
38
/// using the specified TargetData. If successful, the constant result is
39
/// result is returned, if not, null is returned.
40
Constant *ConstantFoldConstantExpression(const ConstantExpr *CE,
41
const TargetData *TD = 0);
43
/// ConstantFoldInstOperands - Attempt to constant fold an instruction with the
44
/// specified operands. If successful, the constant result is returned, if not,
45
/// null is returned. Note that this function can fail when attempting to
46
/// fold instructions like loads and stores, which have no constant expression
49
Constant *ConstantFoldInstOperands(unsigned Opcode, const Type *DestTy,
50
Constant *const *Ops, unsigned NumOps,
51
const TargetData *TD = 0);
53
/// ConstantFoldCompareInstOperands - Attempt to constant fold a compare
54
/// instruction (icmp/fcmp) with the specified operands. If it fails, it
55
/// returns a constant expression of the specified operands.
57
Constant *ConstantFoldCompareInstOperands(unsigned Predicate,
58
Constant *LHS, Constant *RHS,
59
const TargetData *TD = 0);
61
/// ConstantFoldLoadFromConstPtr - Return the value that a load from C would
62
/// produce if it is constant and determinable. If this is not determinable,
64
Constant *ConstantFoldLoadFromConstPtr(Constant *C, const TargetData *TD = 0);
66
/// ConstantFoldLoadThroughGEPConstantExpr - Given a constant and a
67
/// getelementptr constantexpr, return the constant value being addressed by the
68
/// constant expression, or null if something is funny and we can't decide.
69
Constant *ConstantFoldLoadThroughGEPConstantExpr(Constant *C, ConstantExpr *CE);
71
/// canConstantFoldCallTo - Return true if its even possible to fold a call to
72
/// the specified function.
73
bool canConstantFoldCallTo(const Function *F);
75
/// ConstantFoldCall - Attempt to constant fold a call to the specified function
76
/// with the specified arguments, returning null if unsuccessful.
78
ConstantFoldCall(Function *F, Constant *const *Operands, unsigned NumOperands);