[llvm-commits] CVS: llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
Chris Lattner
lattner at cs.uiuc.edu
Sat Oct 4 20:54:01 PDT 2003
Changes in directory llvm/lib/Transforms/Utils:
PromoteMemoryToRegister.cpp updated: 1.42 -> 1.43
---
Log message:
* Minor cleanups
* Eliminate the KillList instance variable, instead, just delete loads and
stores as they are "renamed", and delete allocas when they are done
* Make the 'visited' set an instance variable to avoid passing it on the stack.
---
Diffs of the changes:
Index: llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
diff -u llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp:1.42 llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp:1.43
--- llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp:1.42 Mon Aug 18 09:34:00 2003
+++ llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp Sat Oct 4 20:52:53 2003
@@ -51,7 +51,7 @@
namespace {
struct PromoteMem2Reg {
- const std::vector<AllocaInst*> &Allocas; // the alloca instructions..
+ const std::vector<AllocaInst*> &Allocas; // the alloca instructions..
std::vector<unsigned> VersionNumbers; // Current version counters
DominanceFrontier &DF;
const TargetData &TD;
@@ -60,33 +60,29 @@
std::vector<std::vector<BasicBlock*> > PhiNodes;// Idx corresponds 2 Allocas
- // List of instructions to remove at end of pass
- std::vector<Instruction *> KillList;
-
- std::map<BasicBlock*,
- std::vector<PHINode*> > NewPhiNodes; // the PhiNodes we're adding
+ // NewPhiNodes - The PhiNodes we're adding.
+ std::map<BasicBlock*, std::vector<PHINode*> > NewPhiNodes;
+
+ // Visited - The set of basic blocks the renamer has already visited.
+ std::set<BasicBlock*> Visited;
public:
PromoteMem2Reg(const std::vector<AllocaInst*> &A, DominanceFrontier &df,
- const TargetData &td)
- : Allocas(A), DF(df), TD(td) {}
+ const TargetData &td) : Allocas(A), DF(df), TD(td) {}
void run();
private:
void RenamePass(BasicBlock *BB, BasicBlock *Pred,
- std::vector<Value*> &IncVals,
- std::set<BasicBlock*> &Visited);
+ std::vector<Value*> &IncVals);
bool QueuePhiNode(BasicBlock *BB, unsigned AllocaIdx);
};
} // end of anonymous namespace
void PromoteMem2Reg::run() {
- // If there is nothing to do, bail out...
- if (Allocas.empty()) return;
-
Function &F = *DF.getRoot()->getParent();
+
VersionNumbers.resize(Allocas.size());
for (unsigned i = 0, e = Allocas.size(); i != e; ++i) {
@@ -97,11 +93,6 @@
AllocaLookup[Allocas[i]] = i;
}
-
- // Add each alloca to the KillList. Note: KillList is destroyed MOST recently
- // added to least recently.
- KillList.assign(Allocas.begin(), Allocas.end());
-
// Calculate the set of write-locations for each alloca. This is analogous to
// counting the number of 'redefinitions' of each variable.
std::vector<std::vector<BasicBlock*> > WriteSets;// Idx corresponds to Allocas
@@ -153,27 +144,20 @@
// Walks all basic blocks in the function performing the SSA rename algorithm
// and inserting the phi nodes we marked as necessary
//
- std::set<BasicBlock*> Visited; // The basic blocks we've already visited
- RenamePass(F.begin(), 0, Values, Visited);
+ RenamePass(F.begin(), 0, Values);
+ Visited.clear();
- // Remove all instructions marked by being placed in the KillList...
- //
- while (!KillList.empty()) {
- Instruction *I = KillList.back();
- KillList.pop_back();
+ // Remove the allocas themselves from the function...
+ for (unsigned i = 0, e = Allocas.size(); i != e; ++i) {
+ Instruction *A = Allocas[i];
- // If there are any uses of these instructions left, they must be in
+ // If there are any uses of the alloca instructions left, they must be in
// sections of dead code that were not processed on the dominance frontier.
// Just delete the users now.
//
- while (!I->use_empty()) {
- Instruction *U = cast<Instruction>(I->use_back());
- if (!U->use_empty()) // If uses remain in dead code segment...
- U->replaceAllUsesWith(Constant::getNullValue(U->getType()));
- U->getParent()->getInstList().erase(U);
- }
-
- I->getParent()->getInstList().erase(I);
+ if (!A->use_empty())
+ A->replaceAllUsesWith(Constant::getNullValue(A->getType()));
+ A->getParent()->getInstList().erase(A);
}
}
@@ -215,8 +199,7 @@
}
void PromoteMem2Reg::RenamePass(BasicBlock *BB, BasicBlock *Pred,
- std::vector<Value*> &IncomingVals,
- std::set<BasicBlock*> &Visited) {
+ std::vector<Value*> &IncomingVals) {
// If this is a BB needing a phi node, lookup/create the phinode for each
// variable we need phinodes for.
std::vector<PHINode *> &BBPNs = NewPhiNodes[BB];
@@ -240,9 +223,9 @@
// mark as visited
Visited.insert(BB);
- // keep track of the value of each variable we're watching.. how?
- for (BasicBlock::iterator II = BB->begin(); II != BB->end(); ++II) {
- Instruction *I = II; // get the instruction
+ BasicBlock::iterator II = BB->begin();
+ while (1) {
+ Instruction *I = II++; // get the instruction, increment iterator
if (LoadInst *LI = dyn_cast<LoadInst>(I)) {
if (AllocaInst *Src = dyn_cast<AllocaInst>(LI->getPointerOperand())) {
@@ -252,7 +235,7 @@
// walk the use list of this load and replace all uses with r
LI->replaceAllUsesWith(V);
- KillList.push_back(LI); // Mark the load to be deleted
+ BB->getInstList().erase(LI);
}
}
} else if (StoreInst *SI = dyn_cast<StoreInst>(I)) {
@@ -263,7 +246,7 @@
if (ai != AllocaLookup.end()) {
// what value were we writing?
IncomingVals[ai->second] = SI->getOperand(0);
- KillList.push_back(SI); // Mark the store to be deleted
+ BB->getInstList().erase(SI);
}
}
@@ -271,8 +254,9 @@
// Recurse across our successors
for (unsigned i = 0; i != TI->getNumSuccessors(); i++) {
std::vector<Value*> OutgoingVals(IncomingVals);
- RenamePass(TI->getSuccessor(i), BB, OutgoingVals, Visited);
+ RenamePass(TI->getSuccessor(i), BB, OutgoingVals);
}
+ break;
}
}
}
@@ -284,5 +268,7 @@
///
void PromoteMemToReg(const std::vector<AllocaInst*> &Allocas,
DominanceFrontier &DF, const TargetData &TD) {
+ // If there is nothing to do, bail out...
+ if (Allocas.empty()) return;
PromoteMem2Reg(Allocas, DF, TD).run();
}
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