Local.h revision aff9c270de8de7d1a0bc138d391bc67136bad58e
148486893f46d2e12e926682a3ecb908716bc66c4Chris Lattner//===-- Local.h - Functions to perform local transformations ----*- C++ -*-===// 234695381d626485a560594f162701088079589dfMisha Brukman// 36fbcc26f1460eaee4e0eb8b426fc1ff0c7af11beJohn Criswell// The LLVM Compiler Infrastructure 46fbcc26f1460eaee4e0eb8b426fc1ff0c7af11beJohn Criswell// 57ed47a13356daed2a34cd2209a31f92552e3bdd8Chris Lattner// This file is distributed under the University of Illinois Open Source 67ed47a13356daed2a34cd2209a31f92552e3bdd8Chris Lattner// License. See LICENSE.TXT for details. 734695381d626485a560594f162701088079589dfMisha Brukman// 86fbcc26f1460eaee4e0eb8b426fc1ff0c7af11beJohn Criswell//===----------------------------------------------------------------------===// 9148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner// 10148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner// This family of functions perform various local transformations to the 11148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner// program. 12148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner// 13148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner//===----------------------------------------------------------------------===// 14148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner 15148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner#ifndef LLVM_TRANSFORMS_UTILS_LOCAL_H 16148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner#define LLVM_TRANSFORMS_UTILS_LOCAL_H 17148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner 18d0fde30ce850b78371fd1386338350591f9ff494Brian Gaekenamespace llvm { 19d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 20d68a07650cdb2e18f18f362ba533459aa10e01b6Dan Gohmanclass BasicBlock; 21d68a07650cdb2e18f18f362ba533459aa10e01b6Dan Gohmanclass Instruction; 22d68a07650cdb2e18f18f362ba533459aa10e01b6Dan Gohmanclass Value; 233e57cb98bde04a65623493738d51f2a41e601748Chris Lattnerclass Pass; 24abbc2dd77908f146f73f4cd1abfdfe47faacf43dChris Lattnerclass PHINode; 25cbf99ee973b6c6e6cd9537dae12031382783bc61Chris Lattnerclass AllocaInst; 26c5406b55d58b7378822d5f6316bf253ad0eaa82dChris Lattnerclass ConstantExpr; 2773259caa44b03206d1e39e77a7aa375250b1a193Chris Lattnerclass TargetData; 28aff9c270de8de7d1a0bc138d391bc67136bad58eCedric Venetstruct DbgInfoIntrinsic; 29d68a07650cdb2e18f18f362ba533459aa10e01b6Dan Gohman 30d68a07650cdb2e18f18f362ba533459aa10e01b6Dan Gohmantemplate<typename T> class SmallVectorImpl; 314f02c74a8ec8f4ca83b823146cb9c987ed79b3f6Chris Lattner 32148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner//===----------------------------------------------------------------------===// 333481f24c06b3c9de48bdd99c37547471ca8e761eChris Lattner// Local constant propagation. 34148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner// 35148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner 363e57cb98bde04a65623493738d51f2a41e601748Chris Lattner/// ConstantFoldTerminator - If a terminator instruction is predicated on a 373e57cb98bde04a65623493738d51f2a41e601748Chris Lattner/// constant value, convert it into an unconditional branch to the constant 383e57cb98bde04a65623493738d51f2a41e601748Chris Lattner/// destination. This is a nontrivial operation because the successors of this 393e57cb98bde04a65623493738d51f2a41e601748Chris Lattner/// basic block must have their PHI nodes updated. 403e57cb98bde04a65623493738d51f2a41e601748Chris Lattner/// 4176ae3445f81164aaff9f95123426109c119f27c0Chris Lattnerbool ConstantFoldTerminator(BasicBlock *BB); 42148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner 43148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner//===----------------------------------------------------------------------===// 443481f24c06b3c9de48bdd99c37547471ca8e761eChris Lattner// Local dead code elimination. 45148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner// 46148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner 473e57cb98bde04a65623493738d51f2a41e601748Chris Lattner/// isInstructionTriviallyDead - Return true if the result produced by the 483e57cb98bde04a65623493738d51f2a41e601748Chris Lattner/// instruction is not used, and the instruction has no side effects. 493e57cb98bde04a65623493738d51f2a41e601748Chris Lattner/// 50148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattnerbool isInstructionTriviallyDead(Instruction *I); 51148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner 523481f24c06b3c9de48bdd99c37547471ca8e761eChris Lattner 533481f24c06b3c9de48bdd99c37547471ca8e761eChris Lattner/// RecursivelyDeleteTriviallyDeadInstructions - If the specified value is a 543481f24c06b3c9de48bdd99c37547471ca8e761eChris Lattner/// trivially dead instruction, delete it. If that makes any of its operands 553481f24c06b3c9de48bdd99c37547471ca8e761eChris Lattner/// trivially dead, delete them too, recursively. 564f02c74a8ec8f4ca83b823146cb9c987ed79b3f6Chris Lattner/// 574f02c74a8ec8f4ca83b823146cb9c987ed79b3f6Chris Lattner/// If DeadInst is specified, the vector is filled with the instructions that 584f02c74a8ec8f4ca83b823146cb9c987ed79b3f6Chris Lattner/// are actually deleted. 594f02c74a8ec8f4ca83b823146cb9c987ed79b3f6Chris Lattnervoid RecursivelyDeleteTriviallyDeadInstructions(Value *V, 604f02c74a8ec8f4ca83b823146cb9c987ed79b3f6Chris Lattner SmallVectorImpl<Instruction*> *DeadInst = 0); 613481f24c06b3c9de48bdd99c37547471ca8e761eChris Lattner 62abbc2dd77908f146f73f4cd1abfdfe47faacf43dChris Lattner//===----------------------------------------------------------------------===// 6329874e0dc6c4e55bc384611273343bb358982cc3Chris Lattner// Control Flow Graph Restructuring. 64148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner// 65148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner 66b29714a10af94b6daae437e48a82ae32675f79cbChris Lattner/// MergeBasicBlockIntoOnlyPred - BB is a block with one predecessor and its 67b29714a10af94b6daae437e48a82ae32675f79cbChris Lattner/// predecessor is known to have one successor (BB!). Eliminate the edge 68b29714a10af94b6daae437e48a82ae32675f79cbChris Lattner/// between them, moving the instructions in the predecessor into BB. This 69b29714a10af94b6daae437e48a82ae32675f79cbChris Lattner/// deletes the predecessor block. 70b29714a10af94b6daae437e48a82ae32675f79cbChris Lattner/// 71b29714a10af94b6daae437e48a82ae32675f79cbChris Lattnervoid MergeBasicBlockIntoOnlyPred(BasicBlock *BB); 72b29714a10af94b6daae437e48a82ae32675f79cbChris Lattner 73b29714a10af94b6daae437e48a82ae32675f79cbChris Lattner 743e57cb98bde04a65623493738d51f2a41e601748Chris Lattner/// SimplifyCFG - This function is used to do simplification of a CFG. For 753e57cb98bde04a65623493738d51f2a41e601748Chris Lattner/// example, it adjusts branches to branches to eliminate the extra hop, it 763e57cb98bde04a65623493738d51f2a41e601748Chris Lattner/// eliminates unreachable basic blocks, and does other "peephole" optimization 773e57cb98bde04a65623493738d51f2a41e601748Chris Lattner/// of the CFG. It returns true if a modification was made, possibly deleting 783e57cb98bde04a65623493738d51f2a41e601748Chris Lattner/// the basic block that was pointed to. 793e57cb98bde04a65623493738d51f2a41e601748Chris Lattner/// 803e57cb98bde04a65623493738d51f2a41e601748Chris Lattner/// WARNING: The entry node of a method may not be simplified. 813e57cb98bde04a65623493738d51f2a41e601748Chris Lattner/// 8218961504fc2b299578dba817900a0696cf3ccc4dChris Lattnerbool SimplifyCFG(BasicBlock *BB); 83148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner 84cbf99ee973b6c6e6cd9537dae12031382783bc61Chris Lattner/// DemoteRegToStack - This function takes a virtual register computed by an 858f71b63bead24de7acc6fe7f0487bf56da22d745Chris Lattner/// Instruction and replaces it with a slot in the stack frame, allocated via 86cbf99ee973b6c6e6cd9537dae12031382783bc61Chris Lattner/// alloca. This allows the CFG to be changed around without fear of 87cbf99ee973b6c6e6cd9537dae12031382783bc61Chris Lattner/// invalidating the SSA information for the value. It returns the pointer to 88cbf99ee973b6c6e6cd9537dae12031382783bc61Chris Lattner/// the alloca inserted to create a stack slot for X. 89cbf99ee973b6c6e6cd9537dae12031382783bc61Chris Lattner/// 90a024e8cedab928403818ac79e899cdae2a356c56Anton KorobeynikovAllocaInst *DemoteRegToStack(Instruction &X, bool VolatileLoads = false, 91d68a07650cdb2e18f18f362ba533459aa10e01b6Dan Gohman Instruction *AllocaPoint = 0); 92cbf99ee973b6c6e6cd9537dae12031382783bc61Chris Lattner 9308d14d2469c4f0465f610a204353220ee2ccde9cTanya Lattner/// DemotePHIToStack - This function takes a virtual register computed by a phi 9408d14d2469c4f0465f610a204353220ee2ccde9cTanya Lattner/// node and replaces it with a slot in the stack frame, allocated via alloca. 9508d14d2469c4f0465f610a204353220ee2ccde9cTanya Lattner/// The phi node is deleted and it returns the pointer to the alloca inserted. 96d68a07650cdb2e18f18f362ba533459aa10e01b6Dan GohmanAllocaInst *DemotePHIToStack(PHINode *P, Instruction *AllocaPoint = 0); 9708d14d2469c4f0465f610a204353220ee2ccde9cTanya Lattner 984afc90dacf309999d8b7f6c2b4b0c56af346bab5Devang Patel/// OnlyUsedByDbgIntrinsics - Return true if the instruction I is only used 994afc90dacf309999d8b7f6c2b4b0c56af346bab5Devang Patel/// by DbgIntrinsics. If DbgInUses is specified then the vector is filled 1004afc90dacf309999d8b7f6c2b4b0c56af346bab5Devang Patel/// with DbgInfoIntrinsic that use the instruction I. 1014afc90dacf309999d8b7f6c2b4b0c56af346bab5Devang Patelbool OnlyUsedByDbgInfoIntrinsics(Instruction *I, 1024afc90dacf309999d8b7f6c2b4b0c56af346bab5Devang Patel SmallVectorImpl<DbgInfoIntrinsic *> *DbgInUses = 0); 103d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke} // End llvm namespace 104d0fde30ce850b78371fd1386338350591f9ff494Brian Gaeke 105148a0bfcea5d3267eac02613cfcc8b5fe8894f2cChris Lattner#endif 106