X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FTransforms%2FUtils%2FUnifyFunctionExitNodes.cpp;h=0c2fc0a972b53c931706a5f9fd82bb13563a9e67;hb=7478e275730f5b9fc0651b5600761c8e707e1897;hp=6cdaba53a050f50d28934dc002644e21211bce40;hpb=34437f35e9ecc5891b3f8b50c52adc305dd19228;p=oota-llvm.git

diff --git a/lib/Transforms/Utils/UnifyFunctionExitNodes.cpp b/lib/Transforms/Utils/UnifyFunctionExitNodes.cpp
index 6cdaba53a05..0c2fc0a972b 100644
--- a/lib/Transforms/Utils/UnifyFunctionExitNodes.cpp
+++ b/lib/Transforms/Utils/UnifyFunctionExitNodes.cpp
@@ -15,20 +15,17 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/Utils/UnifyFunctionExitNodes.h"
-#include "llvm/Transforms/Scalar.h"
-#include "llvm/BasicBlock.h"
-#include "llvm/Function.h"
-#include "llvm/Instructions.h"
-#include "llvm/Type.h"
-#include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Type.h"
+#include "llvm/Transforms/Scalar.h"
 using namespace llvm;
 
 char UnifyFunctionExitNodes::ID = 0;
-static RegisterPass<UnifyFunctionExitNodes>
-X("mergereturn", "Unify function exit nodes");
-
-int UnifyFunctionExitNodes::stub;
+INITIALIZE_PASS(UnifyFunctionExitNodes, "mergereturn",
+                "Unify function exit nodes", false, false)
 
 Pass *llvm::createUnifyFunctionExitNodesPass() {
   return new UnifyFunctionExitNodes();
@@ -38,7 +35,7 @@ void UnifyFunctionExitNodes::getAnalysisUsage(AnalysisUsage &AU) const{
   // We preserve the non-critical-edgeness property
   AU.addPreservedID(BreakCriticalEdgesID);
   // This is a cluster of orthogonal Transforms
-  AU.addPreservedID(PromoteMemoryToRegisterID);
+  AU.addPreserved("mem2reg");
   AU.addPreservedID(LowerSwitchID);
 }
 
@@ -53,41 +50,22 @@ bool UnifyFunctionExitNodes::runOnFunction(Function &F) {
   // return.
   //
   std::vector<BasicBlock*> ReturningBlocks;
-  std::vector<BasicBlock*> UnwindingBlocks;
   std::vector<BasicBlock*> UnreachableBlocks;
   for(Function::iterator I = F.begin(), E = F.end(); I != E; ++I)
     if (isa<ReturnInst>(I->getTerminator()))
       ReturningBlocks.push_back(I);
-    else if (isa<UnwindInst>(I->getTerminator()))
-      UnwindingBlocks.push_back(I);
     else if (isa<UnreachableInst>(I->getTerminator()))
       UnreachableBlocks.push_back(I);
 
-  // Handle unwinding blocks first.
-  if (UnwindingBlocks.empty()) {
-    UnwindBlock = 0;
-  } else if (UnwindingBlocks.size() == 1) {
-    UnwindBlock = UnwindingBlocks.front();
-  } else {
-    UnwindBlock = BasicBlock::Create("UnifiedUnwindBlock", &F);
-    new UnwindInst(UnwindBlock);
-
-    for (std::vector<BasicBlock*>::iterator I = UnwindingBlocks.begin(),
-           E = UnwindingBlocks.end(); I != E; ++I) {
-      BasicBlock *BB = *I;
-      BB->getInstList().pop_back();  // Remove the unwind insn
-      BranchInst::Create(UnwindBlock, BB);
-    }
-  }
-
   // Then unreachable blocks.
   if (UnreachableBlocks.empty()) {
-    UnreachableBlock = 0;
+    UnreachableBlock = nullptr;
   } else if (UnreachableBlocks.size() == 1) {
     UnreachableBlock = UnreachableBlocks.front();
   } else {
-    UnreachableBlock = BasicBlock::Create("UnifiedUnreachableBlock", &F);
-    new UnreachableInst(UnreachableBlock);
+    UnreachableBlock = BasicBlock::Create(F.getContext(), 
+                                          "UnifiedUnreachableBlock", &F);
+    new UnreachableInst(F.getContext(), UnreachableBlock);
 
     for (std::vector<BasicBlock*>::iterator I = UnreachableBlocks.begin(),
            E = UnreachableBlocks.end(); I != E; ++I) {
@@ -99,7 +77,7 @@ bool UnifyFunctionExitNodes::runOnFunction(Function &F) {
 
   // Now handle return blocks.
   if (ReturningBlocks.empty()) {
-    ReturnBlock = 0;
+    ReturnBlock = nullptr;
     return false;                          // No blocks return
   } else if (ReturningBlocks.size() == 1) {
     ReturnBlock = ReturningBlocks.front(); // Already has a single return block
@@ -110,35 +88,18 @@ bool UnifyFunctionExitNodes::runOnFunction(Function &F) {
   // nodes (if the function returns values), and convert all of the return
   // instructions into unconditional branches.
   //
-  BasicBlock *NewRetBlock = BasicBlock::Create("UnifiedReturnBlock", &F);
+  BasicBlock *NewRetBlock = BasicBlock::Create(F.getContext(),
+                                               "UnifiedReturnBlock", &F);
 
-  SmallVector<Value *, 4> Phis;
-  unsigned NumRetVals = ReturningBlocks[0]->getTerminator()->getNumOperands();
-  if (NumRetVals == 0)
-    ReturnInst::Create(NULL, NewRetBlock);
-  else if (const StructType *STy = dyn_cast<StructType>(F.getReturnType())) {
-    Instruction *InsertPt = NULL;
-    if (NumRetVals == 0)
-      InsertPt = NewRetBlock->getFirstNonPHI();
-    PHINode *PN = NULL;
-    for (unsigned i = 0; i < NumRetVals; ++i) {
-      if (InsertPt)
-        PN = PHINode::Create(STy->getElementType(i), "UnifiedRetVal." 
-                         + utostr(i), InsertPt);
-      else
-        PN = PHINode::Create(STy->getElementType(i), "UnifiedRetVal." 
-                         + utostr(i), NewRetBlock);
-      Phis.push_back(PN);
-      InsertPt = PN;
-    }
-    ReturnInst::Create(&Phis[0], NumRetVals, NewRetBlock);
-  }
-  else {
+  PHINode *PN = nullptr;
+  if (F.getReturnType()->isVoidTy()) {
+    ReturnInst::Create(F.getContext(), nullptr, NewRetBlock);
+  } else {
     // If the function doesn't return void... add a PHI node to the block...
-    PHINode *PN = PHINode::Create(F.getReturnType(), "UnifiedRetVal");
+    PN = PHINode::Create(F.getReturnType(), ReturningBlocks.size(),
+                         "UnifiedRetVal");
     NewRetBlock->getInstList().push_back(PN);
-    Phis.push_back(PN);
-    ReturnInst::Create(PN, NewRetBlock);
+    ReturnInst::Create(F.getContext(), PN, NewRetBlock);
   }
 
   // Loop over all of the blocks, replacing the return instruction with an
@@ -150,11 +111,8 @@ bool UnifyFunctionExitNodes::runOnFunction(Function &F) {
 
     // Add an incoming element to the PHI node for every return instruction that
     // is merging into this new block...
-    if (!Phis.empty()) {
-      for (unsigned i = 0; i < NumRetVals; ++i) 
-        cast<PHINode>(Phis[i])->addIncoming(BB->getTerminator()->getOperand(i), 
-                                            BB);
-    }
+    if (PN)
+      PN->addIncoming(BB->getTerminator()->getOperand(0), BB);
 
     BB->getInstList().pop_back();  // Remove the return insn
     BranchInst::Create(NewRetBlock, BB);