1 //===-- ConstantFolding.h - Analyze constant folding possibilities --------===//
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 family of functions determines the possibility of performing constant
13 //===----------------------------------------------------------------------===//
15 #ifndef LLVM_ANALYSIS_CONSTANTFOLDING_H
16 #define LLVM_ANALYSIS_CONSTANTFOLDING_H
26 /// ConstantFoldInstruction - Attempt to constant fold the specified
27 /// instruction. If successful, the constant result is returned, if not, null
28 /// is returned. Note that this function can only fail when attempting to fold
29 /// instructions like loads and stores, which have no constant expression form.
31 Constant *ConstantFoldInstruction(Instruction *I, const TargetData *TD = 0);
33 /// ConstantFoldConstantExpression - Attempt to fold the constant expression
34 /// using the specified TargetData. If successful, the constant result is
35 /// result is returned, if not, null is returned.
36 Constant *ConstantFoldConstantExpression(ConstantExpr *CE,
37 const TargetData *TD);
39 /// ConstantFoldInstOperands - Attempt to constant fold an instruction with the
40 /// specified operands. If successful, the constant result is returned, if not,
41 /// null is returned. Note that this function can fail when attempting to
42 /// fold instructions like loads and stores, which have no constant expression
45 Constant *ConstantFoldInstOperands(unsigned Opcode, const Type *DestTy,
46 Constant*const * Ops, unsigned NumOps,
47 const TargetData *TD = 0);
49 /// ConstantFoldCompareInstOperands - Attempt to constant fold a compare
50 /// instruction (icmp/fcmp) with the specified operands. If it fails, it
51 /// returns a constant expression of the specified operands.
53 Constant *ConstantFoldCompareInstOperands(unsigned Predicate,
54 Constant*const * Ops, unsigned NumOps,
55 const TargetData *TD = 0);
58 /// ConstantFoldLoadThroughGEPConstantExpr - Given a constant and a
59 /// getelementptr constantexpr, return the constant value being addressed by the
60 /// constant expression, or null if something is funny and we can't decide.
61 Constant *ConstantFoldLoadThroughGEPConstantExpr(Constant *C, ConstantExpr *CE);
63 /// canConstantFoldCallTo - Return true if its even possible to fold a call to
64 /// the specified function.
65 bool canConstantFoldCallTo(const Function *F);
67 /// ConstantFoldCall - Attempt to constant fold a call to the specified function
68 /// with the specified arguments, returning null if unsuccessful.
70 ConstantFoldCall(Function *F, Constant* const* Operands, unsigned NumOperands);