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	discussion of this change. Boy are my fingers tired. ;-) git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45411 91177308-0d34-0410-b5e6-96231b3b80d8
		
			
				
	
	
		
			92 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			92 lines
		
	
	
		
			3.4 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
//===-- Local.h - Functions to perform local transformations ----*- C++ -*-===//
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//
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//                     The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This family of functions perform various local transformations to the
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// program.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TRANSFORMS_UTILS_LOCAL_H
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#define LLVM_TRANSFORMS_UTILS_LOCAL_H
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#include "llvm/Function.h"
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namespace llvm {
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class Pass;
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class PHINode;
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class AllocaInst;
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class ConstantExpr;
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class TargetData;
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//===----------------------------------------------------------------------===//
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//  Local constant propagation...
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//
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/// doConstantPropagation - Constant prop a specific instruction.  Returns true
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/// and potentially moves the iterator if constant propagation was performed.
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///
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bool doConstantPropagation(BasicBlock::iterator &I, const TargetData *TD = 0);
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/// ConstantFoldTerminator - If a terminator instruction is predicated on a
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/// constant value, convert it into an unconditional branch to the constant
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/// destination.  This is a nontrivial operation because the successors of this
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/// basic block must have their PHI nodes updated.
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///
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bool ConstantFoldTerminator(BasicBlock *BB);
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//===----------------------------------------------------------------------===//
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//  Local dead code elimination...
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//
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/// isInstructionTriviallyDead - Return true if the result produced by the
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/// instruction is not used, and the instruction has no side effects.
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///
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bool isInstructionTriviallyDead(Instruction *I);
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/// dceInstruction - Inspect the instruction at *BBI and figure out if it
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/// isTriviallyDead.  If so, remove the instruction and update the iterator to
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/// point to the instruction that immediately succeeded the original
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/// instruction.
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///
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bool dceInstruction(BasicBlock::iterator &BBI);
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//===----------------------------------------------------------------------===//
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//  Control Flow Graph Restructuring...
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//
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/// SimplifyCFG - This function is used to do simplification of a CFG.  For
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/// example, it adjusts branches to branches to eliminate the extra hop, it
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/// eliminates unreachable basic blocks, and does other "peephole" optimization
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/// of the CFG.  It returns true if a modification was made, possibly deleting
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/// the basic block that was pointed to.
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///
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/// WARNING:  The entry node of a method may not be simplified.
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///
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bool SimplifyCFG(BasicBlock *BB);
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/// DemoteRegToStack - This function takes a virtual register computed by an
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/// Instruction and replaces it with a slot in the stack frame, allocated via
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/// alloca.  This allows the CFG to be changed around without fear of
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/// invalidating the SSA information for the value.  It returns the pointer to
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/// the alloca inserted to create a stack slot for X.
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///
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AllocaInst *DemoteRegToStack(Instruction &X, bool VolatileLoads = false,
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                             Instruction *AllocaPoint = NULL);
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/// DemotePHIToStack - This function takes a virtual register computed by a phi
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/// node and replaces it with a slot in the stack frame, allocated via alloca.
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/// The phi node is deleted and it returns the pointer to the alloca inserted. 
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AllocaInst *DemotePHIToStack(PHINode *P, Instruction *AllocaPoint = NULL);
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} // End llvm namespace
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#endif
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