[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

6 files changed, 33 insertions, 29 deletions

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);
     }