-//===- ConstantProp.cpp - Code to perform Simple Constant Propogation -----===//
+//===- ConstantProp.cpp - Code to perform Simple Constant Propagation -----===//
+//
+// The LLVM Compiler Infrastructure
//
-// This file implements constant propogation and merging:
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements constant propagation and merging:
//
// Specifically, this:
// * Converts instructions like "add int 1, 2" into 3
#include "llvm/Instruction.h"
#include "llvm/Pass.h"
#include "llvm/Support/InstIterator.h"
+#include "Support/Statistic.h"
#include <set>
namespace {
- struct ConstantPropogation : public FunctionPass {
- const char *getPassName() const { return "Simple Constant Propogation"; }
+ Statistic<> NumInstKilled("constprop", "Number of instructions killed");
- inline bool runOnFunction(Function *F);
+ struct ConstantPropagation : public FunctionPass {
+ bool runOnFunction(Function &F);
virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AU.preservesCFG();
+ AU.setPreservesCFG();
}
};
+
+ RegisterOpt<ConstantPropagation> X("constprop","Simple constant propagation");
}
-Pass *createConstantPropogationPass() {
- return new ConstantPropogation();
+Pass *createConstantPropagationPass() {
+ return new ConstantPropagation();
}
-bool ConstantPropogation::runOnFunction(Function *F) {
+bool ConstantPropagation::runOnFunction(Function &F) {
// Initialize the worklist to all of the instructions ready to process...
std::set<Instruction*> WorkList(inst_begin(F), inst_end(F));
bool Changed = false;
if (!I->use_empty()) // Don't muck with dead instructions...
if (Constant *C = ConstantFoldInstruction(I)) {
// Add all of the users of this instruction to the worklist, they might
- // be constant propogatable now...
+ // be constant propagatable now...
for (Value::use_iterator UI = I->use_begin(), UE = I->use_end();
UI != UE; ++UI)
WorkList.insert(cast<Instruction>(*UI));
// Replace all of the uses of a variable with uses of the constant.
I->replaceAllUsesWith(C);
-
+
// We made a change to the function...
Changed = true;
+ ++NumInstKilled;
}
}
return Changed;