[NFC] allocas should use the AllocaAS (#3004)

Currently, when reverse translating, we hardcode either 0 or
`SPIRAS_Private` as the address space for `alloca`s. This is not ideal
as it creates tight coupling with the current AS mappings. Furthermore,
it is not necessary, as the DataLayout holds the AllocaAS, which is what
we need. Hence, this patch changes all hardcoded callsites where we
create an `AllocaInst` to use the DataLayout specified AS. It's NFC as
it does not modify existing behaviour.

Author: AlexVlx

lib/SPIRV/SPIRVReader.cpp

@@ -1663,7 +1663,7 @@ Value *SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
       // execution instance, so emit an alloca instead of a global.
       assert(BB && "OpVariable with Function storage class requires BB");
       IRBuilder<> Builder(BB);
-      AllocaInst *AI = Builder.CreateAlloca(Ty, 0, BV->getName());
+      AllocaInst *AI = Builder.CreateAlloca(Ty, nullptr, BV->getName());
       if (Init) {
         auto *Src = transValue(Init, F, BB);
         const bool IsVolatile = BVar->hasDecorate(DecorationVolatile);
@@ -1777,8 +1777,9 @@ Value *SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
     auto *VLA = static_cast<SPIRVVariableLengthArrayINTEL *>(BV);
     llvm::Type *Ty = transType(BV->getType()->getPointerElementType());
     llvm::Value *ArrSize = transValue(VLA->getOperand(0), F, BB);
-    return mapValue(
-        BV, new AllocaInst(Ty, SPIRAS_Private, ArrSize, BV->getName(), BB));
+    return mapValue(BV,
+                    new AllocaInst(Ty, M->getDataLayout().getAllocaAddrSpace(),
+                                   ArrSize, BV->getName(), BB));
   }
 
   case OpRestoreMemoryINTEL: {
@@ -2247,7 +2248,8 @@ Value *SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
   case OpCopyObject: {
     SPIRVCopyObject *CO = static_cast<SPIRVCopyObject *>(BV);
     auto *Ty = transType(CO->getOperand()->getType());
-    AllocaInst *AI = new AllocaInst(Ty, 0, "", BB);
+    AllocaInst *AI =
+        new AllocaInst(Ty, M->getDataLayout().getAllocaAddrSpace(), "", BB);
     new StoreInst(transValue(CO->getOperand(), F, BB), AI, BB);
     LoadInst *LI = new LoadInst(Ty, AI, "", BB);
     return mapValue(BV, LI);
@@ -2398,7 +2400,8 @@ Value *SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
       if (!HasRtValues)
         return mapValue(BV, ConstantArray::get(AT, CV));
 
-      AllocaInst *Alloca = new AllocaInst(AT, SPIRAS_Private, "", BB);
+      AllocaInst *Alloca =
+          new AllocaInst(AT, M->getDataLayout().getAllocaAddrSpace(), "", BB);
 
       // get pointer to the element of the array
       // store the result of argument
@@ -2417,7 +2420,8 @@ Value *SPIRVToLLVM::transValueWithoutDecoration(SPIRVValue *BV, Function *F,
       if (!HasRtValues)
         return mapValue(BV, ConstantStruct::get(ST, CV));
 
-      AllocaInst *Alloca = new AllocaInst(ST, SPIRAS_Private, "", BB);
+      AllocaInst *Alloca =
+          new AllocaInst(ST, M->getDataLayout().getAllocaAddrSpace(), "", BB);
 
       // get pointer to the element of structure
       // store the result of argument
@@ -3017,7 +3021,8 @@ Value *SPIRVToLLVM::transFixedPointInst(SPIRVInstruction *BI, BasicBlock *BB) {
   Args.reserve(8);
   if (RetTy->getIntegerBitWidth() > 64) {
     llvm::PointerType *RetPtrTy = llvm::PointerType::get(RetTy, SPIRAS_Generic);
-    Value *Alloca = new AllocaInst(RetTy, SPIRAS_Private, "", BB);
+    Value *Alloca =
+        new AllocaInst(RetTy, M->getDataLayout().getAllocaAddrSpace(), "", BB);
     Value *RetValPtr = new AddrSpaceCastInst(Alloca, RetPtrTy, "", BB);
     ArgTys.emplace_back(RetPtrTy);
     Args.emplace_back(RetValPtr);
@@ -3141,7 +3146,8 @@ Value *SPIRVToLLVM::transArbFloatInst(SPIRVInstruction *BI, BasicBlock *BB,
   if (RetTy->getIntegerBitWidth() > 64) {
     llvm::PointerType *RetPtrTy = llvm::PointerType::get(RetTy, SPIRAS_Generic);
     ArgTys.push_back(RetPtrTy);
-    Value *Alloca = new AllocaInst(RetTy, SPIRAS_Private, "", BB);
+    Value *Alloca =
+        new AllocaInst(RetTy, M->getDataLayout().getAllocaAddrSpace(), "", BB);
     Value *RetValPtr = new AddrSpaceCastInst(Alloca, RetPtrTy, "", BB);
     Args.push_back(RetValPtr);
   }

lib/SPIRV/SPIRVToLLVMDbgTran.cpp

@@ -1583,7 +1583,9 @@ SPIRVToLLVMDbgTran::transDebugIntrinsic(const SPIRVExtInst *DebugInst,
       // DIBuilder::insertDeclare doesn't allow to pass nullptr for the Storage
       // parameter. To work around this limitation we create a dummy temp
       // alloca, use it to create llvm.dbg.declare, and then remove the alloca.
-      auto *AI = new AllocaInst(Type::getInt8Ty(M->getContext()), 0, "tmp", BB);
+      auto *AI =
+          new AllocaInst(Type::getInt8Ty(M->getContext()),
+                         M->getDataLayout().getAllocaAddrSpace(), "tmp", BB);
       DbgInstPtr DbgDeclare = DIB.insertDeclare(
           AI, LocalVar.first, GetExpression(Ops[ExpressionIdx]),
           LocalVar.second, BB);

lib/SPIRV/SPIRVToOCL20.cpp

@@ -207,7 +207,7 @@ void SPIRVToOCL20Base::visitCallSPIRVAtomicCmpExchg(CallInst *CI) {
   // value by pointer passed as 2nd argument (aka expected) while SPIR-V
   // instructions returns this new/original value as a resulting value.
   AllocaInst *PExpected = new AllocaInst(
-      MemTy, 0, "expected",
+      MemTy, M->getDataLayout().getAllocaAddrSpace(), "expected",
       CI->getParent()->getParent()->getEntryBlock().getFirstInsertionPt());
   PExpected->setAlignment(Align(MemTy->getScalarSizeInBits() / 8));
 

lib/SPIRV/SPIRVUtil.cpp

@@ -1509,7 +1509,9 @@ Value *getScalarOrArrayConstantInt(BasicBlock::iterator Pos, Type *T,
     auto *AT = ArrayType::get(ET, Len);
     std::vector<Constant *> EV(Len, ConstantInt::get(ET, V, IsSigned));
     auto *CA = ConstantArray::get(AT, EV);
-    auto *Alloca = new AllocaInst(AT, 0, "", Pos);
+    auto *Alloca = new AllocaInst(
+        AT, Pos->getParent()->getParent()->getDataLayout().getAllocaAddrSpace(),
+        "", Pos);
     new StoreInst(CA, Alloca, Pos);
     auto *Zero = ConstantInt::getNullValue(Type::getInt32Ty(T->getContext()));
     Value *Index[] = {Zero, Zero};
@@ -2292,7 +2294,9 @@ bool postProcessBuiltinWithArrayArguments(Function *F,
           auto *T = I->getType();
           if (!T->isArrayTy())
             continue;
-          auto *Alloca = new AllocaInst(T, 0, "", FBegin);
+          auto *Alloca = new AllocaInst(
+              T, F->getParent()->getDataLayout().getAllocaAddrSpace(), "",
+              FBegin);
           new StoreInst(I, Alloca, false, CI->getIterator());
           auto *Zero =
               ConstantInt::getNullValue(Type::getInt32Ty(T->getContext()));