Revert r222039 because of bot failure.

http://lab.llvm.org:8080/green/job/clang-Rlto_master/298/
Hopefully, bot will be green. If not, we will re-submit the commit.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@222287 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Scalar/GVN.cpp

@@ -20,7 +20,6 @@
 #include "llvm/ADT/DepthFirstIterator.h"
 #include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/MapVector.h"
-#include "llvm/ADT/PostOrderIterator.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/Statistic.h"
@@ -710,7 +709,6 @@ namespace {
     void dump(DenseMap<uint32_t, Value*> &d);
     bool iterateOnFunction(Function &F);
     bool performPRE(Function &F);
-    bool performScalarPRE(Instruction *I);
     Value *findLeader(const BasicBlock *BB, uint32_t num);
     void cleanupGlobalSets();
     void verifyRemoved(const Instruction *I) const;
@@ -1731,15 +1729,6 @@ bool GVN::processNonLocalLoad(LoadInst *LI) {
     return false;
   }
 
-  // If this load follows a GEP, see if we can PRE the indices before analyzing.
-  if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(LI->getOperand(0))) {
-    for (GetElementPtrInst::op_iterator OI = GEP->idx_begin(),
-                                        OE = GEP->idx_end();
-         OI != OE; ++OI)
-      if (Instruction *I = dyn_cast<Instruction>(OI->get()))
-        performScalarPRE(I);
-  }
-
   // Step 2: Analyze the availability of the load
   AvailValInBlkVect ValuesPerBlock;
   UnavailBlkVect UnavailableBlocks;
@@ -2442,26 +2431,40 @@ bool GVN::processBlock(BasicBlock *BB) {
   return ChangedFunction;
 }
 
-bool GVN::performScalarPRE(Instruction *CurInst) {
+/// performPRE - Perform a purely local form of PRE that looks for diamond
+/// control flow patterns and attempts to perform simple PRE at the join point.
+bool GVN::performPRE(Function &F) {
+  bool Changed = false;
   SmallVector<std::pair<Value*, BasicBlock*>, 8> predMap;
+  for (BasicBlock *CurrentBlock : depth_first(&F.getEntryBlock())) {
+    // Nothing to PRE in the entry block.
+    if (CurrentBlock == &F.getEntryBlock()) continue;
 
-  if (isa<AllocaInst>(CurInst) || isa<TerminatorInst>(CurInst) ||
+    // Don't perform PRE on a landing pad.
-      isa<PHINode>(CurInst) || CurInst->getType()->isVoidTy() ||
+    if (CurrentBlock->isLandingPad()) continue;
+
+    for (BasicBlock::iterator BI = CurrentBlock->begin(),
+         BE = CurrentBlock->end(); BI != BE; ) {
+      Instruction *CurInst = BI++;
+
+      if (isa<AllocaInst>(CurInst) ||
+          isa<TerminatorInst>(CurInst) || isa<PHINode>(CurInst) ||
+          CurInst->getType()->isVoidTy() ||
           CurInst->mayReadFromMemory() || CurInst->mayHaveSideEffects() ||
           isa<DbgInfoIntrinsic>(CurInst))
-    return false;
+        continue;
 
       // Don't do PRE on compares. The PHI would prevent CodeGenPrepare from
       // sinking the compare again, and it would force the code generator to
       // move the i1 from processor flags or predicate registers into a general
       // purpose register.
       if (isa<CmpInst>(CurInst))
-    return false;
+        continue;
 
       // We don't currently value number ANY inline asm calls.
       if (CallInst *CallI = dyn_cast<CallInst>(CurInst))
         if (CallI->isInlineAsm())
-      return false;
+          continue;
 
       uint32_t ValNo = VN.lookup(CurInst);
 
@@ -2474,11 +2477,10 @@ bool GVN::performScalarPRE(Instruction *CurInst) {
       unsigned NumWith = 0;
       unsigned NumWithout = 0;
       BasicBlock *PREPred = nullptr;
-  BasicBlock *CurrentBlock = CurInst->getParent();
       predMap.clear();
 
-  for (pred_iterator PI = pred_begin(CurrentBlock), PE = pred_end(CurrentBlock);
+      for (pred_iterator PI = pred_begin(CurrentBlock),
-       PI != PE; ++PI) {
+           PE = pred_end(CurrentBlock); PI != PE; ++PI) {
         BasicBlock *P = *PI;
         // We're not interested in PRE where the block is its
         // own predecessor, or in blocks with predecessors
@@ -2509,11 +2511,11 @@ bool GVN::performScalarPRE(Instruction *CurInst) {
       // Don't do PRE when it might increase code size, i.e. when
       // we would need to insert instructions in more than one pred.
       if (NumWithout != 1 || NumWith == 0)
-    return false;
+        continue;
 
       // Don't do PRE across indirect branch.
       if (isa<IndirectBrInst>(PREPred->getTerminator()))
-    return false;
+        continue;
 
       // We can't do PRE safely on a critical edge, so instead we schedule
       // the edge to be split and perform the PRE the next time we iterate
@@ -2521,7 +2523,7 @@ bool GVN::performScalarPRE(Instruction *CurInst) {
       unsigned SuccNum = GetSuccessorNumber(PREPred, CurrentBlock);
       if (isCriticalEdge(PREPred->getTerminator(), SuccNum)) {
         toSplit.push_back(std::make_pair(PREPred->getTerminator(), SuccNum));
-    return false;
+        continue;
       }
 
       // Instantiate the expression in the predecessor that lacked it.
@@ -2550,7 +2552,7 @@ bool GVN::performScalarPRE(Instruction *CurInst) {
       if (!success) {
         DEBUG(verifyRemoved(PREInstr));
         delete PREInstr;
-    return false;
+        continue;
       }
 
       PREInstr->insertBefore(PREPred->getTerminator());
@@ -2563,9 +2565,9 @@ bool GVN::performScalarPRE(Instruction *CurInst) {
       addToLeaderTable(ValNo, PREInstr, PREPred);
 
       // Create a PHI to make the value available in this block.
-  PHINode *Phi =
+      PHINode* Phi = PHINode::Create(CurInst->getType(), predMap.size(),
-      PHINode::Create(CurInst->getType(), predMap.size(),
+                                     CurInst->getName() + ".pre-phi",
-                      CurInst->getName() + ".pre-phi", CurrentBlock->begin());
+                                     CurrentBlock->begin());
       for (unsigned i = 0, e = predMap.size(); i != e; ++i) {
         if (Value *V = predMap[i].first)
           Phi->addIncoming(V, predMap[i].second);
@@ -2581,7 +2583,8 @@ bool GVN::performScalarPRE(Instruction *CurInst) {
         // Because we have added a PHI-use of the pointer value, it has now
         // "escaped" from alias analysis' perspective.  We need to inform
         // AA of this.
-    for (unsigned ii = 0, ee = Phi->getNumIncomingValues(); ii != ee; ++ii) {
+        for (unsigned ii = 0, ee = Phi->getNumIncomingValues(); ii != ee;
+             ++ii) {
           unsigned jj = PHINode::getOperandNumForIncomingValue(ii);
           VN.getAliasAnalysis()->addEscapingUse(Phi->getOperandUse(jj));
         }
@@ -2593,31 +2596,10 @@ bool GVN::performScalarPRE(Instruction *CurInst) {
       removeFromLeaderTable(ValNo, CurInst, CurrentBlock);
 
       DEBUG(dbgs() << "GVN PRE removed: " << *CurInst << '\n');
-  if (MD)
+      if (MD) MD->removeInstruction(CurInst);
-    MD->removeInstruction(CurInst);
       DEBUG(verifyRemoved(CurInst));
       CurInst->eraseFromParent();
-  return true;
+      Changed = true;
-}
-
-/// performPRE - Perform a purely local form of PRE that looks for diamond
-/// control flow patterns and attempts to perform simple PRE at the join point.
-bool GVN::performPRE(Function &F) {
-  bool Changed = false;
-  for (BasicBlock *CurrentBlock : depth_first(&F.getEntryBlock())) {
-    // Nothing to PRE in the entry block.
-    if (CurrentBlock == &F.getEntryBlock())
-      continue;
-
-    // Don't perform PRE on a landing pad.
-    if (CurrentBlock->isLandingPad())
-      continue;
-
-    for (BasicBlock::iterator BI = CurrentBlock->begin(),
-                              BE = CurrentBlock->end();
-         BI != BE;) {
-      Instruction *CurInst = BI++;
-      Changed = performScalarPRE(CurInst);
     }
   }
 
@@ -2655,21 +2637,25 @@ bool GVN::iterateOnFunction(Function &F) {
 
   // Top-down walk of the dominator tree
   bool Changed = false;
+#if 0
+  // Needed for value numbering with phi construction to work.
+  ReversePostOrderTraversal<Function*> RPOT(&F);
+  for (ReversePostOrderTraversal<Function*>::rpo_iterator RI = RPOT.begin(),
+       RE = RPOT.end(); RI != RE; ++RI)
+    Changed |= processBlock(*RI);
+#else
   // Save the blocks this function have before transformation begins. GVN may
   // split critical edge, and hence may invalidate the RPO/DT iterator.
   //
   std::vector<BasicBlock *> BBVect;
   BBVect.reserve(256);
-  // Needed for value numbering with phi construction to work.
+  for (DomTreeNode *X : depth_first(DT->getRootNode()))
-  ReversePostOrderTraversal<Function *> RPOT(&F);
+    BBVect.push_back(X->getBlock());
-  for (ReversePostOrderTraversal<Function *>::rpo_iterator RI = RPOT.begin(),
-                                                           RE = RPOT.end();
-       RI != RE; ++RI)
-    BBVect.push_back(*RI);
 
   for (std::vector<BasicBlock *>::iterator I = BBVect.begin(), E = BBVect.end();
        I != E; I++)
     Changed |= processBlock(*I);
+#endif
 
   return Changed;
 }

test/Analysis/TypeBasedAliasAnalysis/gvn-nonlocal-type-mismatch.ll

@@ -46,12 +46,12 @@ entry:
   br i1 %c, label %if.else, label %if.then
 
 if.then:
-  %t = load i32* %p, !tbaa !3
+  %t = load i32* %p, !tbaa !4
   store i32 %t, i32* %q
   ret void
 
 if.else:
-  %u = load i32* %p, !tbaa !4
+  %u = load i32* %p, !tbaa !3
   store i32 %u, i32* %q
   ret void
 }
@@ -61,11 +61,11 @@ if.else:
 
 ; CHECK: @watch_out_for_another_type_change
 ; CHECK: if.then:
-; CHECK:   store i32 0, i32* %q
+; CHECK:   %t = load i32* %p
+; CHECK:   store i32 %t, i32* %q
 ; CHECK:   ret void
 ; CHECK: if.else:
-; CHECK:   %u = load i32* %p
+; CHECK:   store i32 0, i32* %q
-; CHECK:   store i32 %u, i32* %q
 
 define void @watch_out_for_another_type_change(i1 %c, i32* %p, i32* %p1, i32* %q) nounwind {
 entry:
@@ -74,12 +74,12 @@ entry:
   br i1 %c, label %if.else, label %if.then
 
 if.then:
-  %t = load i32* %p, !tbaa !4
+  %t = load i32* %p, !tbaa !3
   store i32 %t, i32* %q
   ret void
 
 if.else:
-  %u = load i32* %p, !tbaa !3
+  %u = load i32* %p, !tbaa !4
   store i32 %u, i32* %q
   ret void
 }

test/Transforms/GVN/pre-gep-load.ll

@@ -1,49 +0,0 @@
-; RUN: opt < %s -basicaa -gvn -enable-load-pre -S | FileCheck %s
-target datalayout = "e-m:e-i64:64-i128:128-n32:64-S128"
-target triple = "aarch64--linux-gnu"
-
-define double @foo(i32 %stat, i32 %i, double** %p) {
-; CHECK-LABEL: @foo(
-entry:
-  switch i32 %stat, label %sw.default [
-    i32 0, label %sw.bb
-    i32 1, label %sw.bb
-    i32 2, label %sw.bb2
-  ]
-
-sw.bb:                                            ; preds = %entry, %entry
-  %idxprom = sext i32 %i to i64
-  %arrayidx = getelementptr inbounds double** %p, i64 0
-  %0 = load double** %arrayidx, align 8
-  %arrayidx1 = getelementptr inbounds double* %0, i64 %idxprom
-  %1 = load double* %arrayidx1, align 8
-  %sub = fsub double %1, 1.000000e+00
-  %cmp = fcmp olt double %sub, 0.000000e+00
-  br i1 %cmp, label %if.then, label %if.end
-
-if.then:                                          ; preds = %sw.bb
-  br label %return
-
-if.end:                                           ; preds = %sw.bb
-  br label %sw.bb2
-
-sw.bb2:                                           ; preds = %if.end, %entry
-  %idxprom3 = sext i32 %i to i64
-  %arrayidx4 = getelementptr inbounds double** %p, i64 0
-  %2 = load double** %arrayidx4, align 8
-  %arrayidx5 = getelementptr inbounds double* %2, i64 %idxprom3
-  %3 = load double* %arrayidx5, align 8
-; CHECK: sw.bb2:
-; CHECK-NEXT-NOT: sext
-; CHECK-NEXT: phi double [
-; CHECK-NOT: load
-  %sub6 = fsub double 3.000000e+00, %3
-  br label %return
-
-sw.default:                                       ; preds = %entry
-  br label %return
-
-return:                                           ; preds = %sw.default, %sw.bb2, %if.then
-  %retval.0 = phi double [ 0.000000e+00, %sw.default ], [ %sub6, %sw.bb2 ], [ %sub, %if.then ]
-  ret double %retval.0
-}