Revert r333268: [IPSCCP] Use PredicateInfo to propagate facts from...

Reverting this to see if this is causing the failures of the
clang-with-thin-lto-ubuntu bot.

[IPSCCP] Use PredicateInfo to propagate facts from cmp instructions.

This patch updates IPSCCP to use PredicateInfo to propagate
facts to true branches predicated by EQ and to false branches
predicated by NE.

As a follow up, we should be able to extend it to also propagate additional
facts about nonnull.

Reviewers: davide, mssimpso, dberlin, efriedma

Reviewed By: davide, dberlin

Differential Revision: https://reviews.llvm.org/D45330

llvm-svn: 333323

2 files changed, 10 insertions, 134 deletions

diff --git a/llvm/lib/Transforms/IPO/SCCP.cpp b/llvm/lib/Transforms/IPO/SCCP.cpp
index e2bb6f185c3..cc53c4b8c46 100644
--- a/llvm/lib/Transforms/IPO/SCCP.cpp
+++ b/llvm/lib/Transforms/IPO/SCCP.cpp
@@ -1,5 +1,4 @@
 #include "llvm/Transforms/IPO/SCCP.h"
-#include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/Transforms/IPO.h"
 #include "llvm/Transforms/Scalar/SCCP.h"
@@ -9,15 +8,7 @@ using namespace llvm;
 PreservedAnalyses IPSCCPPass::run(Module &M, ModuleAnalysisManager &AM) {
   const DataLayout &DL = M.getDataLayout();
   auto &TLI = AM.getResult<TargetLibraryAnalysis>(M);
-  auto &FAM = AM.getResult<FunctionAnalysisManagerModuleProxy>(M).getManager();
-  auto getPredicateInfo =
-      [&FAM](Function &F) -> std::unique_ptr<PredicateInfo> {
-    return make_unique<PredicateInfo>(F,
-                                      FAM.getResult<DominatorTreeAnalysis>(F),
-                                      FAM.getResult<AssumptionAnalysis>(F));
-  };
-
-  if (!runIPSCCP(M, DL, &TLI, getPredicateInfo))
+  if (!runIPSCCP(M, DL, &TLI))
     return PreservedAnalyses::all();
   return PreservedAnalyses::none();
 }
@@ -43,20 +34,10 @@ public:
     const DataLayout &DL = M.getDataLayout();
     const TargetLibraryInfo *TLI =
         &getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
-
-    auto getPredicateInfo =
-        [this](Function &F) -> std::unique_ptr<PredicateInfo> {
-      return make_unique<PredicateInfo>(
-          F, this->getAnalysis<DominatorTreeWrapperPass>(F).getDomTree(),
-          this->getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F));
-    };
-
-    return runIPSCCP(M, DL, TLI, getPredicateInfo);
+    return runIPSCCP(M, DL, TLI);
   }
 
   void getAnalysisUsage(AnalysisUsage &AU) const override {
-    AU.addRequired<AssumptionCacheTracker>();
-    AU.addRequired<DominatorTreeWrapperPass>();
     AU.addRequired<TargetLibraryInfoWrapperPass>();
   }
 };
@@ -68,7 +49,6 @@ char IPSCCPLegacyPass::ID = 0;
 INITIALIZE_PASS_BEGIN(IPSCCPLegacyPass, "ipsccp",
                       "Interprocedural Sparse Conditional Constant Propagation",
                       false, false)
-INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
 INITIALIZE_PASS_END(IPSCCPLegacyPass, "ipsccp",
                     "Interprocedural Sparse Conditional Constant Propagation",
diff --git a/llvm/lib/Transforms/Scalar/SCCP.cpp b/llvm/lib/Transforms/Scalar/SCCP.cpp
index e0bd3480c2d..27c51f07f1f 100644
--- a/llvm/lib/Transforms/Scalar/SCCP.cpp
+++ b/llvm/lib/Transforms/Scalar/SCCP.cpp
@@ -55,7 +55,6 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/raw_ostream.h"
 #include "llvm/Transforms/Scalar.h"
-#include "llvm/Transforms/Utils/PredicateInfo.h"
 #include <cassert>
 #include <utility>
 #include <vector>
@@ -249,21 +248,7 @@ class SCCPSolver : public InstVisitor<SCCPSolver> {
   using Edge = std::pair<BasicBlock *, BasicBlock *>;
   DenseSet<Edge> KnownFeasibleEdges;
 
-  DenseMap<Function *, std::unique_ptr<PredicateInfo>> PredInfos;
-  DenseMap<Value *, SmallPtrSet<User *, 2>> AdditionalUsers;
-
 public:
-  void addPredInfo(Function &F, std::unique_ptr<PredicateInfo> PI) {
-    PredInfos[&F] = std::move(PI);
-  }
-
-  const PredicateBase *getPredicateInfoFor(Instruction *I) {
-    auto PI = PredInfos.find(I->getParent()->getParent());
-    if (PI == PredInfos.end())
-      return nullptr;
-    return PI->second->getPredicateInfoFor(I);
-  }
-
   SCCPSolver(const DataLayout &DL, const TargetLibraryInfo *tli)
       : DL(DL), TLI(tli) {}
 
@@ -578,26 +563,6 @@ private:
       visit(*I);
   }
 
-  // Add U as additional user of V.
-  void addAdditionalUser(Value *V, User *U) {
-    auto Iter = AdditionalUsers.insert({V, {}});
-    Iter.first->second.insert(U);
-  }
-
-  // Mark I's users as changed, including AdditionalUsers.
-  void markUsersAsChanged(Value *I) {
-    for (User *U : I->users())
-      if (auto *UI = dyn_cast<Instruction>(U))
-        OperandChangedState(UI);
-
-    auto Iter = AdditionalUsers.find(I);
-    if (Iter != AdditionalUsers.end()) {
-      for (User *U : Iter->second)
-        if (auto *UI = dyn_cast<Instruction>(U))
-          OperandChangedState(UI);
-    }
-  }
-
 private:
   friend class InstVisitor<SCCPSolver>;
 
@@ -1192,59 +1157,6 @@ void SCCPSolver::visitCallSite(CallSite CS) {
   Function *F = CS.getCalledFunction();
   Instruction *I = CS.getInstruction();
 
-  if (auto *II = dyn_cast<IntrinsicInst>(I)) {
-    if (II->getIntrinsicID() == Intrinsic::ssa_copy) {
-      if (ValueState[I].isOverdefined())
-        return;
-
-      auto *PI = getPredicateInfoFor(I);
-      if (!PI)
-        return;
-
-      auto *PBranch = dyn_cast<PredicateBranch>(getPredicateInfoFor(I));
-      if (!PBranch)
-        return mergeInValue(ValueState[I], I, getValueState(PI->OriginalOp));
-
-      Value *CopyOf = I->getOperand(0);
-      Value *Cond = PBranch->Condition;
-
-      // Everything below relies on the condition being a comparison.
-      auto *Cmp = dyn_cast<CmpInst>(Cond);
-      if (!Cmp)
-        return mergeInValue(ValueState[I], I, getValueState(PI->OriginalOp));
-
-      Value *CmpOp0 = Cmp->getOperand(0);
-      Value *CmpOp1 = Cmp->getOperand(1);
-      if (CopyOf != CmpOp0 && CopyOf != CmpOp1)
-        return mergeInValue(ValueState[I], I, getValueState(PI->OriginalOp));
-
-      if (CmpOp0 != CopyOf)
-        std::swap(CmpOp0, CmpOp1);
-
-      LatticeVal OriginalVal = getValueState(CopyOf);
-      LatticeVal EqVal = getValueState(CmpOp1);
-      LatticeVal &IV = ValueState[I];
-      if (PBranch->TrueEdge && Cmp->getPredicate() == CmpInst::ICMP_EQ) {
-        addAdditionalUser(CmpOp1, I);
-        if (OriginalVal.isConstant())
-          mergeInValue(IV, I, OriginalVal);
-        else
-          mergeInValue(IV, I, EqVal);
-        return;
-      }
-      if (!PBranch->TrueEdge && Cmp->getPredicate() == CmpInst::ICMP_NE) {
-        addAdditionalUser(CmpOp1, I);
-        if (OriginalVal.isConstant())
-          mergeInValue(IV, I, OriginalVal);
-        else
-          mergeInValue(IV, I, EqVal);
-        return;
-      }
-
-      return mergeInValue(IV, I, getValueState(PBranch->OriginalOp));
-    }
-  }
-
   // The common case is that we aren't tracking the callee, either because we
   // are not doing interprocedural analysis or the callee is indirect, or is
   // external.  Handle these cases first.
@@ -1356,7 +1268,9 @@ void SCCPSolver::Solve() {
       // since all of its users will have already been marked as overdefined
       // Update all of the users of this instruction's value.
       //
-      markUsersAsChanged(I);
+      for (User *U : I->users())
+        if (auto *UI = dyn_cast<Instruction>(U))
+          OperandChangedState(UI);
     }
 
     // Process the instruction work list.
@@ -1373,7 +1287,9 @@ void SCCPSolver::Solve() {
       // Update all of the users of this instruction's value.
       //
       if (I->getType()->isStructTy() || !getValueState(I).isOverdefined())
-        markUsersAsChanged(I);
+        for (User *U : I->users())
+          if (auto *UI = dyn_cast<Instruction>(U))
+            OperandChangedState(UI);
     }
 
     // Process the basic block work list.
@@ -1939,9 +1855,8 @@ static void findReturnsToZap(Function &F,
   }
 }
 
-bool llvm::runIPSCCP(
-    Module &M, const DataLayout &DL, const TargetLibraryInfo *TLI,
-    function_ref<std::unique_ptr<PredicateInfo>(Function &)> getPredicateInfo) {
+bool llvm::runIPSCCP(Module &M, const DataLayout &DL,
+                     const TargetLibraryInfo *TLI) {
   SCCPSolver Solver(DL, TLI);
 
   // Loop over all functions, marking arguments to those with their addresses
@@ -1950,7 +1865,6 @@ bool llvm::runIPSCCP(
     if (F.isDeclaration())
       continue;
 
-    Solver.addPredInfo(F, getPredicateInfo(F));
     // Determine if we can track the function's return values. If so, add the
     // function to the solver's set of return-tracked functions.
     if (canTrackReturnsInterprocedurally(&F))
@@ -2069,24 +1983,6 @@ bool llvm::runIPSCCP(
       F.getBasicBlockList().erase(DeadBB);
     }
     BlocksToErase.clear();
-
-    for (BasicBlock &BB : F) {
-      for (BasicBlock::iterator BI = BB.begin(), E = BB.end(); BI != E;) {
-        Instruction *Inst = &*BI++;
-        if (const PredicateBase *PI = Solver.getPredicateInfoFor(Inst)) {
-          if (auto *II = dyn_cast<IntrinsicInst>(Inst)) {
-            if (II->getIntrinsicID() == Intrinsic::ssa_copy) {
-              Value *Op = II->getOperand(0);
-              Inst->replaceAllUsesWith(Op);
-              Inst->eraseFromParent();
-              continue;
-            }
-          }
-          Inst->replaceAllUsesWith(PI->OriginalOp);
-          Inst->eraseFromParent();
-        }
-      }
-    }
   }
 
   // If we inferred constant or undef return values for a function, we replaced