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Enhance RecursivelyDeleteTriviallyDeadInstructions to optionally 

return a list of deleted instructions.

llvm-svn: 60193
This commit is contained in:
Chris Lattner 2008-11-27 23:14:34 +00:00
parent 96e2dbe008
commit 1cb4f72706
2 changed files with 21 additions and 9 deletions
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8
llvm/include/llvm/Transforms/Utils/Local.h
View File

@ -24,7 +24,7 @@ class PHINode;
class AllocaInst;
class ConstantExpr;
class TargetData;
//===----------------------------------------------------------------------===//
// Local constant propagation.
//
@ -49,7 +49,11 @@ bool isInstructionTriviallyDead(Instruction *I);
/// RecursivelyDeleteTriviallyDeadInstructions - If the specified value is a
/// trivially dead instruction, delete it. If that makes any of its operands
/// trivially dead, delete them too, recursively.
void RecursivelyDeleteTriviallyDeadInstructions(Value *V);
///
/// If DeadInst is specified, the vector is filled with the instructions that
/// are actually deleted.
void RecursivelyDeleteTriviallyDeadInstructions(Value *V,
SmallVectorImpl<Instruction*> *DeadInst = 0);
//===----------------------------------------------------------------------===//
// Control Flow Graph Restructuring...

22
llvm/lib/Transforms/Utils/Local.cpp
View File

@ -176,7 +176,11 @@ bool llvm::isInstructionTriviallyDead(Instruction *I) {
/// RecursivelyDeleteTriviallyDeadInstructions - If the specified value is a
/// trivially dead instruction, delete it. If that makes any of its operands
/// trivially dead, delete them too, recursively.
void llvm::RecursivelyDeleteTriviallyDeadInstructions(Value *V) {
///
/// If DeadInst is specified, the vector is filled with the instructions that
/// are actually deleted.
void llvm::RecursivelyDeleteTriviallyDeadInstructions(Value *V,
SmallVectorImpl<Instruction*> *DeadInst) {
Instruction *I = dyn_cast<Instruction>(V);
if (!I || !I->use_empty()) return;
@ -186,12 +190,16 @@ void llvm::RecursivelyDeleteTriviallyDeadInstructions(Value *V) {
while (!Insts.empty()) {
I = *Insts.begin();
Insts.erase(I);
if (isInstructionTriviallyDead(I)) {
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
if (Instruction *U = dyn_cast<Instruction>(I->getOperand(i)))
Insts.insert(U);
I->eraseFromParent();
}
if (!isInstructionTriviallyDead(I))
continue;
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
if (Instruction *U = dyn_cast<Instruction>(I->getOperand(i)))
Insts.insert(U);
I->eraseFromParent();
if (DeadInst)
DeadInst->push_back(I);
}
}