[llvm] [SPIR-V] Insert a bitcast before load/store instruction to keep SPIR-V code valid (PR #84069)

[Michal Paszkowski via llvm-commits]

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@@ -705,33 +714,37 @@ SPIRVType *SPIRVGlobalRegistry::createSPIRVType(
     }
     return getOpTypeFunction(RetTy, ParamTypes, MIRBuilder);
   }
-  if (auto PType = dyn_cast<PointerType>(Ty)) {
-    SPIRVType *SpvElementType;
-    // At the moment, all opaque pointers correspond to i8 element type.
-    // TODO: change the implementation once opaque pointers are supported
-    // in the SPIR-V specification.
-    SpvElementType = getOrCreateSPIRVIntegerType(8, MIRBuilder);
-    // Get access to information about available extensions
-    const SPIRVSubtarget *ST =
-        static_cast<const SPIRVSubtarget *>(&MIRBuilder.getMF().getSubtarget());
-    auto SC = addressSpaceToStorageClass(PType->getAddressSpace(), *ST);
-    // Null pointer means we have a loop in type definitions, make and
-    // return corresponding OpTypeForwardPointer.
-    if (SpvElementType == nullptr) {
-      if (!ForwardPointerTypes.contains(Ty))
-        ForwardPointerTypes[PType] = getOpTypeForwardPointer(SC, MIRBuilder);
-      return ForwardPointerTypes[PType];
-    }
-    // If we have forward pointer associated with this type, use its register
-    // operand to create OpTypePointer.
-    if (ForwardPointerTypes.contains(PType)) {
-      Register Reg = getSPIRVTypeID(ForwardPointerTypes[PType]);
-      return getOpTypePointer(SC, SpvElementType, MIRBuilder, Reg);
-    }
-
-    return getOrCreateSPIRVPointerType(SpvElementType, MIRBuilder, SC);
+  unsigned AddrSpace = 0xFFFF;
+  if (auto PType = dyn_cast<TypedPointerType>(Ty))
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michalpaszkowski wrote:

I did not realize that TypedPointerType will remain available after the opaque pointer transition, I thought that the type will be removed in the coming months. Though it does not look like that is the case -- good :)
Not necessarily in this patch, but we might consider removing GR->getOrCreateSPIRVPointerType() completely and assume to always pass TypedPointerType to GR->getOrCreateSPIRVType(). Possibly this could help resolve some issues. We could also remove special handling of pointer types in DuplicatesTracker and just lookup based on TypedPointerType.

https://github.com/llvm/llvm-project/pull/84069