[ConstnatFolding] Teach the folder how to fold ConstantVector

A ConstantVector can have ConstantExpr operands and vice versa.
However, the folder had no ability to fold ConstantVectors which, in
some cases, was an optimization barrier.

Instead, rephrase the folder in terms of Constants instead of
ConstantExprs and teach callers how to deal with failure.

llvm-svn: 277099

10 files changed, 105 insertions, 98 deletions

diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index 1a6a54b9a76..7ee3e8cb4d4 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -714,10 +714,8 @@ Constant *CastGEPIndices(Type *SrcElemTy, ArrayRef<Constant *> Ops,
     return nullptr;
 
   Constant *C = ConstantExpr::getGetElementPtr(SrcElemTy, Ops[0], NewIdxs);
-  if (auto *CE = dyn_cast<ConstantExpr>(C)) {
-    if (Constant *Folded = ConstantFoldConstantExpression(CE, DL, TLI))
-      C = Folded;
-  }
+  if (Constant *Folded = ConstantFoldConstant(C, DL, TLI))
+    C = Folded;
 
   return C;
 }
@@ -775,10 +773,8 @@ Constant *SymbolicallyEvaluateGEP(const GEPOperator *GEP,
           Constant *Res = ConstantExpr::getPtrToInt(Ptr, CE->getType());
           Res = ConstantExpr::getSub(Res, CE->getOperand(1));
           Res = ConstantExpr::getIntToPtr(Res, ResTy);
-          if (auto *ResCE = dyn_cast<ConstantExpr>(Res))
-            if (auto *FoldedRes =
-                    ConstantFoldConstantExpression(ResCE, DL, TLI))
-              Res = FoldedRes;
+          if (auto *FoldedRes = ConstantFoldConstant(Res, DL, TLI))
+            Res = FoldedRes;
           return Res;
         }
       }
@@ -968,12 +964,59 @@ Constant *ConstantFoldInstOperandsImpl(const Value *InstOrCE, Type *DestTy,
 // Constant Folding public APIs
 //===----------------------------------------------------------------------===//
 
+namespace {
+
+Constant *
+ConstantFoldConstantImpl(const Constant *C, const DataLayout &DL,
+                         const TargetLibraryInfo *TLI,
+                         SmallDenseMap<Constant *, Constant *> &FoldedOps) {
+  if (!isa<ConstantVector>(C) && !isa<ConstantExpr>(C))
+    return nullptr;
+
+  SmallVector<Constant *, 8> Ops;
+  for (const Use &NewU : C->operands()) {
+    auto *NewC = cast<Constant>(&NewU);
+    // Recursively fold the ConstantExpr's operands. If we have already folded
+    // a ConstantExpr, we don't have to process it again.
+    if (isa<ConstantVector>(NewC) || isa<ConstantExpr>(NewC)) {
+      auto It = FoldedOps.find(NewC);
+      if (It == FoldedOps.end()) {
+        if (auto *FoldedC =
+                ConstantFoldConstantImpl(NewC, DL, TLI, FoldedOps)) {
+          NewC = FoldedC;
+          FoldedOps.insert({NewC, FoldedC});
+        } else {
+          FoldedOps.insert({NewC, NewC});
+        }
+      } else {
+        NewC = It->second;
+      }
+    }
+    Ops.push_back(NewC);
+  }
+
+  if (auto *CE = dyn_cast<ConstantExpr>(C)) {
+    if (CE->isCompare())
+      return ConstantFoldCompareInstOperands(CE->getPredicate(), Ops[0], Ops[1],
+                                             DL, TLI);
+
+    return ConstantFoldInstOperandsImpl(CE, CE->getType(), CE->getOpcode(), Ops,
+                                        DL, TLI);
+  }
+
+  assert(isa<ConstantVector>(C));
+  return ConstantVector::get(Ops);
+}
+
+} // end anonymous namespace
+
 Constant *llvm::ConstantFoldInstruction(Instruction *I, const DataLayout &DL,
                                         const TargetLibraryInfo *TLI) {
   // Handle PHI nodes quickly here...
   if (auto *PN = dyn_cast<PHINode>(I)) {
     Constant *CommonValue = nullptr;
 
+    SmallDenseMap<Constant *, Constant *> FoldedOps;
     for (Value *Incoming : PN->incoming_values()) {
       // If the incoming value is undef then skip it.  Note that while we could
       // skip the value if it is equal to the phi node itself we choose not to
@@ -986,9 +1029,8 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I, const DataLayout &DL,
       if (!C)
         return nullptr;
       // Fold the PHI's operands.
-      if (auto *NewC = dyn_cast<ConstantExpr>(C))
-        if (auto *FoldedC = ConstantFoldConstantExpression(NewC, DL, TLI))
-          C = FoldedC;
+      if (auto *FoldedC = ConstantFoldConstantImpl(C, DL, TLI, FoldedOps))
+        C = FoldedC;
       // If the incoming value is a different constant to
       // the one we saw previously, then give up.
       if (CommonValue && C != CommonValue)
@@ -996,7 +1038,6 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I, const DataLayout &DL,
       CommonValue = C;
     }
 
-
     // If we reach here, all incoming values are the same constant or undef.
     return CommonValue ? CommonValue : UndefValue::get(PN->getType());
   }
@@ -1006,13 +1047,13 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I, const DataLayout &DL,
   if (!all_of(I->operands(), [](Use &U) { return isa<Constant>(U); }))
     return nullptr;
 
+  SmallDenseMap<Constant *, Constant *> FoldedOps;
   SmallVector<Constant *, 8> Ops;
   for (const Use &OpU : I->operands()) {
     auto *Op = cast<Constant>(&OpU);
     // Fold the Instruction's operands.
-    if (auto *NewCE = dyn_cast<ConstantExpr>(Op))
-      if (auto *FoldedOp = ConstantFoldConstantExpression(NewCE, DL, TLI))
-        Op = FoldedOp;
+    if (auto *FoldedOp = ConstantFoldConstantImpl(Op, DL, TLI, FoldedOps))
+      Op = FoldedOp;
 
     Ops.push_back(Op);
   }
@@ -1040,48 +1081,10 @@ Constant *llvm::ConstantFoldInstruction(Instruction *I, const DataLayout &DL,
   return ConstantFoldInstOperands(I, Ops, DL, TLI);
 }
 
-namespace {
-
-Constant *ConstantFoldConstantExpressionImpl(
-    const ConstantExpr *CE, const DataLayout &DL, const TargetLibraryInfo *TLI,
-    SmallDenseMap<ConstantExpr *, Constant *> &FoldedOps) {
-  SmallVector<Constant *, 8> Ops;
-  for (const Use &NewU : CE->operands()) {
-    auto *NewC = cast<Constant>(&NewU);
-    // Recursively fold the ConstantExpr's operands. If we have already folded
-    // a ConstantExpr, we don't have to process it again.
-    if (auto *NewCE = dyn_cast<ConstantExpr>(NewC)) {
-      auto It = FoldedOps.find(NewCE);
-      if (It == FoldedOps.end()) {
-        if (auto *FoldedC =
-                ConstantFoldConstantExpressionImpl(NewCE, DL, TLI, FoldedOps)) {
-          NewC = FoldedC;
-          FoldedOps.insert({NewCE, FoldedC});
-        } else {
-          FoldedOps.insert({NewCE, NewCE});
-        }
-      } else {
-        NewC = It->second;
-      }
-    }
-    Ops.push_back(NewC);
-  }
-
-  if (CE->isCompare())
-    return ConstantFoldCompareInstOperands(CE->getPredicate(), Ops[0], Ops[1],
-                                           DL, TLI);
-
-  return ConstantFoldInstOperandsImpl(CE, CE->getType(), CE->getOpcode(), Ops,
-                                      DL, TLI);
-}
-
-} // end anonymous namespace
-
-Constant *llvm::ConstantFoldConstantExpression(const ConstantExpr *CE,
-                                               const DataLayout &DL,
-                                               const TargetLibraryInfo *TLI) {
-  SmallDenseMap<ConstantExpr *, Constant *> FoldedOps;
-  return ConstantFoldConstantExpressionImpl(CE, DL, TLI, FoldedOps);
+Constant *llvm::ConstantFoldConstant(const Constant *C, const DataLayout &DL,
+                                     const TargetLibraryInfo *TLI) {
+  SmallDenseMap<Constant *, Constant *> FoldedOps;
+  return ConstantFoldConstantImpl(C, DL, TLI, FoldedOps);
 }
 
 Constant *llvm::ConstantFoldInstOperands(Instruction *I,
diff --git a/llvm/lib/Analysis/Lint.cpp b/llvm/lib/Analysis/Lint.cpp
index fdf5f55dab9..0b374bad129 100644
--- a/llvm/lib/Analysis/Lint.cpp
+++ b/llvm/lib/Analysis/Lint.cpp
@@ -680,9 +680,9 @@ Value *Lint::findValueImpl(Value *V, bool OffsetOk,
   if (Instruction *Inst = dyn_cast<Instruction>(V)) {
     if (Value *W = SimplifyInstruction(Inst, *DL, TLI, DT, AC))
       return findValueImpl(W, OffsetOk, Visited);
-  } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
-    if (Value *W = ConstantFoldConstantExpression(CE, *DL, TLI))
-      if (W != V)
+  } else if (auto *C = dyn_cast<Constant>(V)) {
+    if (Value *W = ConstantFoldConstant(C, *DL, TLI))
+      if (W && W != V)
         return findValueImpl(W, OffsetOk, Visited);
   }
 
diff --git a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
index 90ed275ed97..c5f415cb529 100644
--- a/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
@@ -1764,7 +1764,7 @@ const MCExpr *AsmPrinter::lowerConstant(const Constant *CV) {
     // If the code isn't optimized, there may be outstanding folding
     // opportunities. Attempt to fold the expression using DataLayout as a
     // last resort before giving up.
-    if (Constant *C = ConstantFoldConstantExpression(CE, getDataLayout()))
+    if (Constant *C = ConstantFoldConstant(CE, getDataLayout()))
       if (C != CE)
         return lowerConstant(C);
 
@@ -2299,7 +2299,7 @@ static void emitGlobalConstantImpl(const DataLayout &DL, const Constant *CV,
       // If the constant expression's size is greater than 64-bits, then we have
       // to emit the value in chunks. Try to constant fold the value and emit it
       // that way.
-      Constant *New = ConstantFoldConstantExpression(CE, DL);
+      Constant *New = ConstantFoldConstant(CE, DL);
       if (New && New != CE)
         return emitGlobalConstantImpl(DL, New, AP);
     }
diff --git a/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp b/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
index f2bd585a8f3..e627be0b23d 100644
--- a/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
+++ b/llvm/lib/Target/NVPTX/NVPTXAsmPrinter.cpp
@@ -1848,9 +1848,9 @@ void NVPTXAsmPrinter::bufferLEByte(const Constant *CPV, int Bytes,
         ConvertIntToBytes<>(ptr, int32);
         aggBuffer->addBytes(ptr, 4, Bytes);
         break;
-      } else if (const ConstantExpr *Cexpr = dyn_cast<ConstantExpr>(CPV)) {
-        if (const ConstantInt *constInt = dyn_cast<ConstantInt>(
-                ConstantFoldConstantExpression(Cexpr, DL))) {
+      } else if (const auto *Cexpr = dyn_cast<ConstantExpr>(CPV)) {
+        if (const auto *constInt = dyn_cast_or_null<ConstantInt>(
+                ConstantFoldConstant(Cexpr, DL))) {
           int int32 = (int)(constInt->getZExtValue());
           ConvertIntToBytes<>(ptr, int32);
           aggBuffer->addBytes(ptr, 4, Bytes);
@@ -1871,8 +1871,8 @@ void NVPTXAsmPrinter::bufferLEByte(const Constant *CPV, int Bytes,
         aggBuffer->addBytes(ptr, 8, Bytes);
         break;
       } else if (const ConstantExpr *Cexpr = dyn_cast<ConstantExpr>(CPV)) {
-        if (const ConstantInt *constInt = dyn_cast<ConstantInt>(
-                ConstantFoldConstantExpression(Cexpr, DL))) {
+        if (const auto *constInt = dyn_cast_or_null<ConstantInt>(
+                ConstantFoldConstant(Cexpr, DL))) {
           long long int64 = (long long)(constInt->getZExtValue());
           ConvertIntToBytes<>(ptr, int64);
           aggBuffer->addBytes(ptr, 8, Bytes);
@@ -2074,8 +2074,8 @@ NVPTXAsmPrinter::lowerConstantForGV(const Constant *CV, bool ProcessingGeneric)
     // If the code isn't optimized, there may be outstanding folding
     // opportunities. Attempt to fold the expression using DataLayout as a
     // last resort before giving up.
-    if (Constant *C = ConstantFoldConstantExpression(CE, getDataLayout()))
-      if (C != CE)
+    if (Constant *C = ConstantFoldConstant(CE, getDataLayout()))
+      if (C && C != CE)
         return lowerConstantForGV(C, ProcessingGeneric);
 
     // Otherwise report the problem to the user.
diff --git a/llvm/lib/Transforms/IPO/GlobalOpt.cpp b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
index 99b12d4db0d..967aeb32d86 100644
--- a/llvm/lib/Transforms/IPO/GlobalOpt.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalOpt.cpp
@@ -2079,10 +2079,10 @@ OptimizeGlobalVars(Module &M, TargetLibraryInfo *TLI,
       GV->setLinkage(GlobalValue::InternalLinkage);
     // Simplify the initializer.
     if (GV->hasInitializer())
-      if (ConstantExpr *CE = dyn_cast<ConstantExpr>(GV->getInitializer())) {
+      if (auto *C = dyn_cast<Constant>(GV->getInitializer())) {
         auto &DL = M.getDataLayout();
-        Constant *New = ConstantFoldConstantExpression(CE, DL, TLI);
-        if (New && New != CE)
+        Constant *New = ConstantFoldConstant(C, DL, TLI);
+        if (New && New != C)
           GV->setInitializer(New);
       }
 
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
index d41c449c7d2..840feca3338 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -161,9 +161,8 @@ Value *InstCombiner::EvaluateInDifferentType(Value *V, Type *Ty,
   if (Constant *C = dyn_cast<Constant>(V)) {
     C = ConstantExpr::getIntegerCast(C, Ty, isSigned /*Sext or ZExt*/);
     // If we got a constantexpr back, try to simplify it with DL info.
-    if (ConstantExpr *CE = dyn_cast<ConstantExpr>(C))
-      if (Constant *FoldedC = ConstantFoldConstantExpression(CE, DL, TLI))
-        C = FoldedC;
+    if (Constant *FoldedC = ConstantFoldConstant(C, DL, TLI))
+      C = FoldedC;
     return C;
   }
 
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
index 08e16a7ee1a..279eaad0174 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp
@@ -194,8 +194,10 @@ static Value *GetShiftedValue(Value *V, unsigned NumBits, bool isLeftShift,
     else
       V = IC.Builder->CreateLShr(C, NumBits);
     // If we got a constantexpr back, try to simplify it with TD info.
-    if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V))
-      V = ConstantFoldConstantExpression(CE, DL, IC.getTargetLibraryInfo());
+    if (auto *C = dyn_cast<Constant>(V))
+      if (auto *FoldedC =
+              ConstantFoldConstant(C, DL, IC.getTargetLibraryInfo()))
+        V = FoldedC;
     return V;
   }
 
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index 377ccb9c37f..6e4c823901a 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2981,7 +2981,7 @@ static bool AddReachableCodeToWorklist(BasicBlock *BB, const DataLayout &DL,
   Worklist.push_back(BB);
 
   SmallVector<Instruction*, 128> InstrsForInstCombineWorklist;
-  DenseMap<ConstantExpr*, Constant*> FoldedConstants;
+  DenseMap<Constant *, Constant *> FoldedConstants;
 
   do {
     BB = Worklist.pop_back_val();
@@ -3017,17 +3017,17 @@ static bool AddReachableCodeToWorklist(BasicBlock *BB, const DataLayout &DL,
       // See if we can constant fold its operands.
       for (User::op_iterator i = Inst->op_begin(), e = Inst->op_end(); i != e;
            ++i) {
-        ConstantExpr *CE = dyn_cast<ConstantExpr>(i);
-        if (CE == nullptr)
+        if (!isa<ConstantVector>(i) && !isa<ConstantExpr>(i))
           continue;
 
-        Constant *&FoldRes = FoldedConstants[CE];
+        auto *C = cast<Constant>(i);
+        Constant *&FoldRes = FoldedConstants[C];
         if (!FoldRes)
-          FoldRes = ConstantFoldConstantExpression(CE, DL, TLI);
+          FoldRes = ConstantFoldConstant(C, DL, TLI);
         if (!FoldRes)
-          FoldRes = CE;
+          FoldRes = C;
 
-        if (FoldRes != CE) {
+        if (FoldRes != C) {
           *i = FoldRes;
           MadeIRChange = true;
         }
diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp
index a35a1062cbc..6f2ce243f5f 100644
--- a/llvm/lib/Transforms/Scalar/GVN.cpp
+++ b/llvm/lib/Transforms/Scalar/GVN.cpp
@@ -725,8 +725,9 @@ static Value *CoerceAvailableValueToLoadType(Value *StoredVal, Type *LoadedTy,
   assert(CanCoerceMustAliasedValueToLoad(StoredVal, LoadedTy, DL) &&
          "precondition violation - materialization can't fail");
 
-  if (auto *CExpr = dyn_cast<ConstantExpr>(StoredVal))
-    StoredVal = ConstantFoldConstantExpression(CExpr, DL);
+  if (auto *C = dyn_cast<Constant>(StoredVal))
+    if (auto *FoldedStoredVal = ConstantFoldConstant(C, DL))
+      StoredVal = FoldedStoredVal;
 
   // If this is already the right type, just return it.
   Type *StoredValTy = StoredVal->getType();
@@ -759,8 +760,9 @@ static Value *CoerceAvailableValueToLoadType(Value *StoredVal, Type *LoadedTy,
         StoredVal = IRB.CreateIntToPtr(StoredVal, LoadedTy);
     }
 
-    if (auto *CExpr = dyn_cast<ConstantExpr>(StoredVal))
-      StoredVal = ConstantFoldConstantExpression(CExpr, DL);
+    if (auto *C = dyn_cast<ConstantExpr>(StoredVal))
+      if (auto *FoldedStoredVal = ConstantFoldConstant(C, DL))
+        StoredVal = FoldedStoredVal;
 
     return StoredVal;
   }
@@ -804,8 +806,9 @@ static Value *CoerceAvailableValueToLoadType(Value *StoredVal, Type *LoadedTy,
       StoredVal = IRB.CreateBitCast(StoredVal, LoadedTy, "bitcast");
   }
 
-  if (auto *CExpr = dyn_cast<ConstantExpr>(StoredVal))
-    StoredVal = ConstantFoldConstantExpression(CExpr, DL);
+  if (auto *C = dyn_cast<Constant>(StoredVal))
+    if (auto *FoldedStoredVal = ConstantFoldConstant(C, DL))
+      StoredVal = FoldedStoredVal;
 
   return StoredVal;
 }
diff --git a/llvm/lib/Transforms/Utils/Evaluator.cpp b/llvm/lib/Transforms/Utils/Evaluator.cpp
index cd130abf451..008ee505b39 100644
--- a/llvm/lib/Transforms/Utils/Evaluator.cpp
+++ b/llvm/lib/Transforms/Utils/Evaluator.cpp
@@ -203,9 +203,9 @@ bool Evaluator::EvaluateBlock(BasicBlock::iterator CurInst,
         return false;  // no volatile/atomic accesses.
       }
       Constant *Ptr = getVal(SI->getOperand(1));
-      if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ptr)) {
+      if (auto *FoldedPtr = ConstantFoldConstant(Ptr, DL, TLI)) {
         DEBUG(dbgs() << "Folding constant ptr expression: " << *Ptr);
-        Ptr = ConstantFoldConstantExpression(CE, DL, TLI);
+        Ptr = FoldedPtr;
         DEBUG(dbgs() << "; To: " << *Ptr << "\n");
       }
       if (!isSimpleEnoughPointerToCommit(Ptr)) {
@@ -249,8 +249,8 @@ bool Evaluator::EvaluateBlock(BasicBlock::iterator CurInst,
               Constant * const IdxList[] = {IdxZero, IdxZero};
 
               Ptr = ConstantExpr::getGetElementPtr(nullptr, Ptr, IdxList);
-              if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ptr))
-                Ptr = ConstantFoldConstantExpression(CE, DL, TLI);
+              if (auto *FoldedPtr = ConstantFoldConstant(Ptr, DL, TLI))
+                Ptr = FoldedPtr;
 
             // If we can't improve the situation by introspecting NewTy,
             // we have to give up.
@@ -324,8 +324,8 @@ bool Evaluator::EvaluateBlock(BasicBlock::iterator CurInst,
       }
 
       Constant *Ptr = getVal(LI->getOperand(0));
-      if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Ptr)) {
-        Ptr = ConstantFoldConstantExpression(CE, DL, TLI);
+      if (auto *FoldedPtr = ConstantFoldConstant(Ptr, DL, TLI)) {
+        Ptr = FoldedPtr;
         DEBUG(dbgs() << "Found a constant pointer expression, constant "
               "folding: " << *Ptr << "\n");
       }
@@ -512,8 +512,8 @@ bool Evaluator::EvaluateBlock(BasicBlock::iterator CurInst,
     }
 
     if (!CurInst->use_empty()) {
-      if (ConstantExpr *CE = dyn_cast<ConstantExpr>(InstResult))
-        InstResult = ConstantFoldConstantExpression(CE, DL, TLI);
+      if (auto *FoldedInstResult = ConstantFoldConstant(InstResult, DL, TLI))
+        InstResult = FoldedInstResult;
 
       setVal(&*CurInst, InstResult);
     }