[SPIR-V] Change return value of mapType function (#3871)

It's a follow up change for #3856

Signed-off-by: Dmitry Sidorov <dmitry.sidorov@intel.com>

Author: MrSidims

llvm-spirv/lib/SPIRV/SPIRVWriter.cpp

@@ -1827,10 +1827,11 @@ LLVMToSPIRVBase::transValueWithoutDecoration(Value *V, SPIRVBasicBlock *BB,
 
 SPIRVType *LLVMToSPIRVBase::mapType(Type *T, SPIRVType *BT) {
   auto EmplaceStatus = TypeMap.try_emplace(T, BT);
-  (void)EmplaceStatus;
   // TODO: Uncomment the assertion, once the type mapping issue is resolved
   // assert(EmplaceStatus.second && "The type was already added to the map");
   SPIRVDBG(dbgs() << "[mapType] " << *T << " => "; spvdbgs() << *BT << '\n');
+  if (!EmplaceStatus.second)
+    return TypeMap[T];
   return BT;
 }
 

llvm-spirv/test/pointer_type_mapping.ll

@@ -5,8 +5,8 @@
 ; CHECK: Name [[#NAME:]] "struct._ZTS6Object.Object"
 ; CHECK-COUNT-1: TypeStruct [[#NAME]]
 ; TODO add check count one and remove unused, when the type mapping bug is fixed
-; CHECK: TypePointer [[#UNUSED:]] {{.*}} [[#NAME]]
 ; CHECK: TypePointer [[#PTRTY:]] {{.*}} [[#NAME]]
+; CHECK: TypePointer [[#UNUSED:]] {{.*}} [[#NAME]]
 ; CHECK: FunctionParameter [[#PTRTY]]
 ; CHECK-NOT: FunctionParameter [[#UNUSED]]