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
27 /// ConstantFoldInstruction - Attempt to constant fold the specified
28 /// instruction. If successful, the constant result is returned, if not, null
29 /// is returned. Note that this function can only fail when attempting to fold
30 /// instructions like loads and stores, which have no constant expression form.
32 Constant *ConstantFoldInstruction(Instruction *I, LLVMContext &Context,
33 const TargetData *TD = 0);
35 /// ConstantFoldConstantExpression - Attempt to fold the constant expression
36 /// using the specified TargetData. If successful, the constant result is
37 /// result is returned, if not, null is returned.
38 Constant *ConstantFoldConstantExpression(ConstantExpr *CE, LLVMContext &Context,
39 const TargetData *TD = 0);
41 /// ConstantFoldInstOperands - Attempt to constant fold an instruction with the
42 /// specified operands. If successful, the constant result is returned, if not,
43 /// null is returned. Note that this function can fail when attempting to
44 /// fold instructions like loads and stores, which have no constant expression
47 Constant *ConstantFoldInstOperands(unsigned Opcode, const Type *DestTy,
48 Constant*const * Ops, unsigned NumOps,
50 const TargetData *TD = 0);
52 /// ConstantFoldCompareInstOperands - Attempt to constant fold a compare
53 /// instruction (icmp/fcmp) with the specified operands. If it fails, it
54 /// returns a constant expression of the specified operands.
56 Constant *ConstantFoldCompareInstOperands(unsigned Predicate,
57 Constant*const * Ops, unsigned NumOps,
59 const TargetData *TD = 0);
62 /// ConstantFoldLoadThroughGEPConstantExpr - Given a constant and a
63 /// getelementptr constantexpr, return the constant value being addressed by the
64 /// constant expression, or null if something is funny and we can't decide.
65 Constant *ConstantFoldLoadThroughGEPConstantExpr(Constant *C, ConstantExpr *CE,
66 LLVMContext &Context);
68 /// canConstantFoldCallTo - Return true if its even possible to fold a call to
69 /// the specified function.
70 bool canConstantFoldCallTo(const Function *F);
72 /// ConstantFoldCall - Attempt to constant fold a call to the specified function
73 /// with the specified arguments, returning null if unsuccessful.
75 ConstantFoldCall(Function *F, Constant* const* Operands, unsigned NumOperands);