PR14055: Implement support for sub-vector operations in SROA.

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

diff --git a/lib/Transforms/Scalar/ADCE.cpp b/lib/Transforms/Scalar/ADCE.cpp
index c5561995deb64c7dcc6852afe9c070f751869acc..b344952cc5fcaed42a60e05442db327d9bc65204 100644 (file)
--- a/lib/Transforms/Scalar/ADCE.cpp
+++ b/lib/Transforms/Scalar/ADCE.cpp
@@ -9,7 +9,7 @@
 //
 // This file implements the Aggressive Dead Code Elimination pass.  This pass
 // optimistically assumes that all instructions are dead until proven otherwise,
-// allowing it to eliminate dead computations that other DCE passes do not 
+// allowing it to eliminate dead computations that other DCE passes do not
 // catch, particularly involving loop computations.
 //
 //===----------------------------------------------------------------------===//
@@ -18,99 +18,61 @@
 #include "llvm/Transforms/Scalar.h"
 #include "llvm/BasicBlock.h"
 #include "llvm/Instructions.h"
+#include "llvm/IntrinsicInst.h"
 #include "llvm/Pass.h"
 #include "llvm/Support/CFG.h"
-#include "llvm/Support/Compiler.h"
 #include "llvm/Support/InstIterator.h"
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
-
-
 using namespace llvm;
 
 STATISTIC(NumRemoved, "Number of instructions removed");
 
 namespace {
-  struct VISIBILITY_HIDDEN ADCE : public FunctionPass {
+  struct ADCE : public FunctionPass {
     static char ID; // Pass identification, replacement for typeid
-    ADCE() : FunctionPass((intptr_t)&ID) {}
-    
+    ADCE() : FunctionPass(ID) {
+      initializeADCEPass(*PassRegistry::getPassRegistry());
+    }
+
     virtual bool runOnFunction(Function& F);
-    
+
     virtual void getAnalysisUsage(AnalysisUsage& AU) const {
       AU.setPreservesCFG();
     }
-    
+
   };
 }
 
 char ADCE::ID = 0;
-static RegisterPass<ADCE> X("adce", "Aggressive Dead Code Elimination");
+INITIALIZE_PASS(ADCE, "adce", "Aggressive Dead Code Elimination", false, false)
 
 bool ADCE::runOnFunction(Function& F) {
   SmallPtrSet<Instruction*, 128> alive;
   SmallVector<Instruction*, 128> worklist;
-  
-  SmallPtrSet<BasicBlock*, 64> reachable;
-  SmallVector<BasicBlock*, 16> unreachable;
-  
-  // First, collect the set of reachable blocks ...
-  for (df_ext_iterator<BasicBlock*, SmallPtrSet<BasicBlock*, 64> >
-       DI = df_ext_begin(&F.getEntryBlock(), reachable),
-       DE = df_ext_end(&F.getEntryBlock(), reachable); DI != DE; ++DI)
-    ; // Deliberately empty, df_ext_iterator will fill in the set.
-  
-  // ... and then invert it into the list of unreachable ones.  These
-  // blocks will be removed from the function.
-  for (Function::iterator FI = F.begin(), FE = F.end(); FI != FE; ++FI)
-    if (!reachable.count(FI))
-      unreachable.push_back(FI);
-  
-  // Prepare to remove blocks by removing the PHI node entries for those blocks
-  // in their successors, and remove them from reference counting.
-  for (SmallVector<BasicBlock*, 16>::iterator UI = unreachable.begin(),
-       UE = unreachable.end(); UI != UE; ++UI) {
-    BasicBlock* BB = *UI;
-    for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB);
-         SI != SE; ++SI) {
-      BasicBlock* succ = *SI;
-      BasicBlock::iterator succ_inst = succ->begin();
-      while (PHINode* P = dyn_cast<PHINode>(succ_inst)) {
-        P->removeIncomingValue(BB);
-        ++succ_inst;
-      }
-    }
-    
-    BB->dropAllReferences();
-  }
-  
-  // Finally, erase the unreachable blocks.
-  for (SmallVector<BasicBlock*, 16>::iterator UI = unreachable.begin(),
-       UE = unreachable.end(); UI != UE; ++UI)
-    (*UI)->eraseFromParent();
-  
+
   // Collect the set of "root" instructions that are known live.
   for (inst_iterator I = inst_begin(F), E = inst_end(F); I != E; ++I)
     if (isa<TerminatorInst>(I.getInstructionIterator()) ||
-        I->mayWriteToMemory()) {
+        isa<DbgInfoIntrinsic>(I.getInstructionIterator()) ||
+        isa<LandingPadInst>(I.getInstructionIterator()) ||
+        I->mayHaveSideEffects()) {
       alive.insert(I.getInstructionIterator());
       worklist.push_back(I.getInstructionIterator());
     }
-  
+
   // Propagate liveness backwards to operands.
   while (!worklist.empty()) {
-    Instruction* curr = worklist.back();
-    worklist.pop_back();
-    
+    Instruction* curr = worklist.pop_back_val();
     for (Instruction::op_iterator OI = curr->op_begin(), OE = curr->op_end();
          OI != OE; ++OI)
       if (Instruction* Inst = dyn_cast<Instruction>(OI))
         if (alive.insert(Inst))
           worklist.push_back(Inst);
   }
-  
+
   // The inverse of the live set is the dead set.  These are those instructions
   // which have no side effects and do not influence the control flow or return
   // value of the function, and may therefore be deleted safely.
@@ -120,13 +82,13 @@ bool ADCE::runOnFunction(Function& F) {
       worklist.push_back(I.getInstructionIterator());
       I->dropAllReferences();
     }
-  
+
   for (SmallVector<Instruction*, 1024>::iterator I = worklist.begin(),
        E = worklist.end(); I != E; ++I) {
-    NumRemoved++;
+    ++NumRemoved;
     (*I)->eraseFromParent();
   }
-    
+
   return !worklist.empty();
 }