[llvm] [SPIR-V] Implement SPV_KHR_untyped_pointers extension (PR #201233)

[Juan Manuel Martinez Caamaño via llvm-commits]

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@@ -185,9 +185,13 @@ static SPIRVTypeInst getArgSPIRVType(const Function &F, unsigned ArgIdx,
   // spv_assign_ptr_type intrinsic or otherwise use default pointer element
   // type.
   if (hasPointeeTypeAttr(Arg)) {
+    // byval/byref/sret carry the aggregate layout in the pointee type, so keep
+    // a typed pointer here. An untyped one drops the type and breaks the
+    // argument ABI on the way back from SPIR-V.
     return GR->getOrCreateSPIRVPointerType(
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jmmartinez wrote:

Maybe we need a `getOrCreateSPIRVTypedPointerType`.The `ForcedType` meaning wasn't obvious at first.

https://github.com/llvm/llvm-project/pull/201233