Resurrect r191017 " GVN proceeds in the presence of dead code" plus a fix to PR17307...

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

diff --git a/lib/Transforms/Scalar/DCE.cpp b/lib/Transforms/Scalar/DCE.cpp
index cb78207d760bc0d9b82bc1e01fee2ea63fced7de..e8a090af40c316f1d3d09b53d00b926f67b633aa 100644 (file)
--- a/lib/Transforms/Scalar/DCE.cpp
+++ b/lib/Transforms/Scalar/DCE.cpp
@@ -18,13 +18,12 @@
 
 #define DEBUG_TYPE "dce"
 #include "llvm/Transforms/Scalar.h"
-#include "llvm/Transforms/Utils/Local.h"
-#include "llvm/Instruction.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/IR/Instruction.h"
 #include "llvm/Pass.h"
-#include "llvm/Support/Compiler.h"
 #include "llvm/Support/InstIterator.h"
-#include "llvm/ADT/Statistic.h"
-#include <set>
+#include "llvm/Target/TargetLibraryInfo.h"
+#include "llvm/Transforms/Utils/Local.h"
 using namespace llvm;
 
 STATISTIC(DIEEliminated, "Number of insts removed by DIE pass");
@@ -34,17 +33,22 @@ 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) {
+      initializeDeadInstEliminationPass(*PassRegistry::getPassRegistry());
+    }
     virtual bool runOnBasicBlock(BasicBlock &BB) {
+      TargetLibraryInfo *TLI = getAnalysisIfAvailable<TargetLibraryInfo>();
       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, TLI)) {
+          Inst->eraseFromParent();
           Changed = true;
           ++DIEEliminated;
-        } else
-          ++DI;
+        }
+      }
       return Changed;
     }
 
@@ -55,8 +59,8 @@ namespace {
 }
 
 char DeadInstElimination::ID = 0;
-static RegisterPass<DeadInstElimination>
-X("die", "Dead Instruction Elimination");
+INITIALIZE_PASS(DeadInstElimination, "die",
+                "Dead Instruction Elimination", false, false)
 
 Pass *llvm::createDeadInstEliminationPass() {
   return new DeadInstElimination();
@@ -69,7 +73,9 @@ namespace {
   //
   struct DCE : public FunctionPass {
     static char ID; // Pass identification, replacement for typeid
-    DCE() : FunctionPass(&ID) {}
+    DCE() : FunctionPass(ID) {
+      initializeDCEPass(*PassRegistry::getPassRegistry());
+    }
 
     virtual bool runOnFunction(Function &F);
 
@@ -80,9 +86,11 @@ namespace {
 }
 
 char DCE::ID = 0;
-static RegisterPass<DCE> Y("dce", "Dead Code Elimination");
+INITIALIZE_PASS(DCE, "dce", "Dead Code Elimination", false, false)
 
 bool DCE::runOnFunction(Function &F) {
+  TargetLibraryInfo *TLI = getAnalysisIfAvailable<TargetLibraryInfo>();
+
   // Start out with all of the instructions in the worklist...
   std::vector<Instruction*> WorkList;
   for (inst_iterator i = inst_begin(F), e = inst_end(F); i != e; ++i)
@@ -97,7 +105,7 @@ bool DCE::runOnFunction(Function &F) {
     Instruction *I = WorkList.back();
     WorkList.pop_back();
 
-    if (isInstructionTriviallyDead(I)) {       // If the instruction is dead.
+    if (isInstructionTriviallyDead(I, TLI)) { // If the instruction is dead.
       // Loop over all of the values that the instruction uses, if there are
       // instructions being used, add them to the worklist, because they might
       // go dead after this one is removed.
@@ -110,12 +118,8 @@ bool DCE::runOnFunction(Function &F) {
       I->eraseFromParent();
 
       // 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.erase(WI);
-          --WI;
-        }
+      WorkList.erase(std::remove(WorkList.begin(), WorkList.end(), I),
+                     WorkList.end());
 
       MadeChange = true;
       ++DCEEliminated;