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//===-- BasicBlockUtils.cpp - BasicBlock Utilities -------------------------==//
//
// This family of functions perform manipulations on basic blocks, and
// instructions contained within basic blocks.
//
//===----------------------------------------------------------------------===//
#include "llvm/Transforms/Utils/BasicBlockUtils.h"
#include "llvm/Function.h"
#include "llvm/Instruction.h"
#include <algorithm>
// ReplaceInstWithValue - Replace all uses of an instruction (specified by BI)
// with a value, then remove and delete the original instruction.
//
void ReplaceInstWithValue(BasicBlock::InstListType &BIL,
BasicBlock::iterator &BI, Value *V) {
Instruction *I = *BI;
// Replaces all of the uses of the instruction with uses of the value
I->replaceAllUsesWith(V);
// Remove the unneccesary instruction now...
BIL.remove(BI);
// Make sure to propogate a name if there is one already...
if (I->hasName() && !V->hasName())
V->setName(I->getName(), BIL.getParent()->getSymbolTable());
// Remove the dead instruction now...
delete I;
}
// ReplaceInstWithInst - Replace the instruction specified by BI with the
// instruction specified by I. The original instruction is deleted and BI is
// updated to point to the new instruction.
//
void ReplaceInstWithInst(BasicBlock::InstListType &BIL,
BasicBlock::iterator &BI, Instruction *I) {
assert(I->getParent() == 0 &&
"ReplaceInstWithInst: Instruction already inserted into basic block!");
// Insert the new instruction into the basic block...
BI = BIL.insert(BI, I)+1; // Increment BI to point to instruction to delete
// Replace all uses of the old instruction, and delete it.
ReplaceInstWithValue(BIL, BI, I);
// Move BI back to point to the newly inserted instruction
--BI;
}
// ReplaceInstWithInst - Replace the instruction specified by From with the
// instruction specified by To. Note that this is slower than providing an
// iterator directly, because the basic block containing From must be searched
// for the instruction.
//
void ReplaceInstWithInst(Instruction *From, Instruction *To) {
BasicBlock *BB = From->getParent();
BasicBlock::InstListType &BIL = BB->getInstList();
BasicBlock::iterator BI = find(BIL.begin(), BIL.end(), From);
assert(BI != BIL.end() && "Inst not in it's parents BB!");
ReplaceInstWithInst(BIL, BI, To);
}
// InsertInstBeforeInst - Insert 'NewInst' into the basic block that 'Existing'
// is already in, and put it right before 'Existing'. This instruction should
// only be used when there is no iterator to Existing already around. The
// returned iterator points to the new instruction.
//
BasicBlock::iterator InsertInstBeforeInst(Instruction *NewInst,
Instruction *Existing) {
BasicBlock *BB = Existing->getParent();
BasicBlock::InstListType &BIL = BB->getInstList();
BasicBlock::iterator BI = find(BIL.begin(), BIL.end(), Existing);
assert(BI != BIL.end() && "Inst not in it's parents BB!");
return BIL.insert(BI, NewInst);
}
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