move some functions, add a comment.

[oota-llvm.git] / lib / Transforms / Scalar / DCE.cpp

diff --git a/lib/Transforms/Scalar/DCE.cpp b/lib/Transforms/Scalar/DCE.cpp
index 539dd22d47d102b54de8e61995a71e5125c91571..39940c35da5d5f076857ec31822b62b2dcaf292b 100644 (file)
--- a/lib/Transforms/Scalar/DCE.cpp
+++ b/lib/Transforms/Scalar/DCE.cpp
@@ -21,7 +21,6 @@
 #include "llvm/Transforms/Utils/Local.h"
 #include "llvm/Instruction.h"
 #include "llvm/Pass.h"
-#include "llvm/Support/Compiler.h"
 #include "llvm/Support/InstIterator.h"
 #include "llvm/ADT/Statistic.h"
 #include <set>
@@ -34,17 +33,19 @@ namespace {
   //===--------------------------------------------------------------------===//
   // DeadInstElimination pass implementation
   //
-  struct VISIBILITY_HIDDEN DeadInstElimination : public BasicBlockPass {
+  struct DeadInstElimination : public BasicBlockPass {
     static char ID; // Pass identification, replacement for typeid
-    DeadInstElimination() : BasicBlockPass(intptr_t(&ID)) {}
+    DeadInstElimination() : BasicBlockPass(&ID) {}
     virtual bool runOnBasicBlock(BasicBlock &BB) {
       bool Changed = false;
-      for (BasicBlock::iterator DI = BB.begin(); DI != BB.end(); )
-        if (dceInstruction(DI)) {
+      for (BasicBlock::iterator DI = BB.begin(); DI != BB.end(); ) {
+        Instruction *Inst = DI++;
+        if (isInstructionTriviallyDead(Inst)) {
+          Inst->eraseFromParent();
           Changed = true;
           ++DIEEliminated;
-        } else
-          ++DI;
+        }
+      }
       return Changed;
     }
 
@@ -52,11 +53,12 @@ namespace {
       AU.setPreservesCFG();
     }
   };
-
-  char DeadInstElimination::ID = 0;
-  RegisterPass<DeadInstElimination> X("die", "Dead Instruction Elimination");
 }
 
+char DeadInstElimination::ID = 0;
+static RegisterPass<DeadInstElimination>
+X("die", "Dead Instruction Elimination");
+
 Pass *llvm::createDeadInstEliminationPass() {
   return new DeadInstElimination();
 }
@@ -68,7 +70,7 @@ namespace {
   //
   struct DCE : public FunctionPass {
     static char ID; // Pass identification, replacement for typeid
-    DCE() : FunctionPass((intptr_t)&ID) {}
+    DCE() : FunctionPass(&ID) {}
 
     virtual bool runOnFunction(Function &F);
 
@@ -76,11 +78,11 @@ namespace {
       AU.setPreservesCFG();
     }
  };
-
-  char DCE::ID = 0;
-  RegisterPass<DCE> Y("dce", "Dead Code Elimination");
 }
 
+char DCE::ID = 0;
+static RegisterPass<DCE> Y("dce", "Dead Code Elimination");
+
 bool DCE::runOnFunction(Function &F) {
   // Start out with all of the instructions in the worklist...
   std::vector<Instruction*> WorkList;
@@ -110,11 +112,12 @@ bool DCE::runOnFunction(Function &F) {
 
       // Remove the instruction from the worklist if it still exists in it.
       for (std::vector<Instruction*>::iterator WI = WorkList.begin();
-           WI != WorkList.end(); ++WI)
-        if (*WI == I) {
+           WI != WorkList.end(); ) {
+        if (*WI == I)
           WI = WorkList.erase(WI);
-          --WI;
-        }
+        else
+          ++WI;
+      }
 
       MadeChange = true;
       ++DCEEliminated;