1 //===-- InstructionSimplify.h - Fold instructions into simpler forms ------===//
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 simpler forms
11 // that do not require creating new instructions. This does constant folding
12 // ("add i32 1, 1" -> "2") but can also handle non-constant operands, either
13 // returning a constant ("and i32 %x, 0" -> "0") or an already existing value
14 // ("and i32 %x, %x" -> "%x"). If the simplification is also an instruction
15 // then it dominates the original instruction.
17 //===----------------------------------------------------------------------===//
19 #ifndef LLVM_ANALYSIS_INSTRUCTIONSIMPLIFY_H
20 #define LLVM_ANALYSIS_INSTRUCTIONSIMPLIFY_H
28 /// SimplifyAddInst - Given operands for an Add, see if we can
29 /// fold the result. If not, this returns null.
30 Value *SimplifyAddInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW,
31 const TargetData *TD = 0, const DominatorTree *DT = 0);
33 /// SimplifySubInst - Given operands for a Sub, see if we can
34 /// fold the result. If not, this returns null.
35 Value *SimplifySubInst(Value *LHS, Value *RHS, bool isNSW, bool isNUW,
36 const TargetData *TD = 0, const DominatorTree *DT = 0);
38 /// SimplifyMulInst - Given operands for a Mul, see if we can
39 /// fold the result. If not, this returns null.
40 Value *SimplifyMulInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
41 const DominatorTree *DT = 0);
43 /// SimplifySDivInst - Given operands for an SDiv, see if we can
44 /// fold the result. If not, this returns null.
45 Value *SimplifySDivInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
46 const DominatorTree *DT = 0);
48 /// SimplifyUDivInst - Given operands for a UDiv, see if we can
49 /// fold the result. If not, this returns null.
50 Value *SimplifyUDivInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
51 const DominatorTree *DT = 0);
53 /// SimplifyShlInst - Given operands for a Shl, see if we can
54 /// fold the result. If not, this returns null.
55 Value *SimplifyShlInst(Value *Op0, Value *Op1, const TargetData *TD = 0,
56 const DominatorTree *DT = 0);
58 /// SimplifyLShrInst - Given operands for a LShr, see if we can
59 /// fold the result. If not, this returns null.
60 Value *SimplifyLShrInst(Value *Op0, Value *Op1, const TargetData *TD = 0,
61 const DominatorTree *DT = 0);
63 /// SimplifyAShrInst - Given operands for a AShr, see if we can
64 /// fold the result. If not, this returns null.
65 Value *SimplifyAShrInst(Value *Op0, Value *Op1, const TargetData *TD = 0,
66 const DominatorTree *DT = 0);
68 /// SimplifyAndInst - Given operands for an And, see if we can
69 /// fold the result. If not, this returns null.
70 Value *SimplifyAndInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
71 const DominatorTree *DT = 0);
73 /// SimplifyOrInst - Given operands for an Or, see if we can
74 /// fold the result. If not, this returns null.
75 Value *SimplifyOrInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
76 const DominatorTree *DT = 0);
78 /// SimplifyXorInst - Given operands for a Xor, see if we can
79 /// fold the result. If not, this returns null.
80 Value *SimplifyXorInst(Value *LHS, Value *RHS, const TargetData *TD = 0,
81 const DominatorTree *DT = 0);
83 /// SimplifyICmpInst - Given operands for an ICmpInst, see if we can
84 /// fold the result. If not, this returns null.
85 Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
86 const TargetData *TD = 0,
87 const DominatorTree *DT = 0);
89 /// SimplifyFCmpInst - Given operands for an FCmpInst, see if we can
90 /// fold the result. If not, this returns null.
91 Value *SimplifyFCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
92 const TargetData *TD = 0,
93 const DominatorTree *DT = 0);
95 /// SimplifySelectInst - Given operands for a SelectInst, see if we can fold
96 /// the result. If not, this returns null.
97 Value *SimplifySelectInst(Value *Cond, Value *TrueVal, Value *FalseVal,
98 const TargetData *TD = 0,
99 const DominatorTree *DT = 0);
101 /// SimplifyGEPInst - Given operands for an GetElementPtrInst, see if we can
102 /// fold the result. If not, this returns null.
103 Value *SimplifyGEPInst(Value * const *Ops, unsigned NumOps,
104 const TargetData *TD = 0, const DominatorTree *DT = 0);
106 //=== Helper functions for higher up the class hierarchy.
109 /// SimplifyCmpInst - Given operands for a CmpInst, see if we can
110 /// fold the result. If not, this returns null.
111 Value *SimplifyCmpInst(unsigned Predicate, Value *LHS, Value *RHS,
112 const TargetData *TD = 0, const DominatorTree *DT = 0);
114 /// SimplifyBinOp - Given operands for a BinaryOperator, see if we can
115 /// fold the result. If not, this returns null.
116 Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS,
117 const TargetData *TD = 0, const DominatorTree *DT = 0);
119 /// SimplifyInstruction - See if we can compute a simplified version of this
120 /// instruction. If not, this returns null.
121 Value *SimplifyInstruction(Instruction *I, const TargetData *TD = 0,
122 const DominatorTree *DT = 0);
125 /// ReplaceAndSimplifyAllUses - Perform From->replaceAllUsesWith(To) and then
126 /// delete the From instruction. In addition to a basic RAUW, this does a
127 /// recursive simplification of the updated instructions. This catches
128 /// things where one simplification exposes other opportunities. This only
129 /// simplifies and deletes scalar operations, it does not change the CFG.
131 void ReplaceAndSimplifyAllUses(Instruction *From, Value *To,
132 const TargetData *TD = 0,
133 const DominatorTree *DT = 0);
134 } // end namespace llvm