[llvm] [Offload] Ensure all `llvm::Error`s are handled (PR #137339)

[Ross Brunton via llvm-commits]

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@@ -422,16 +432,19 @@ ol_impl_result_t olMemcpy_impl(ol_queue_handle_t Queue, void *DstPtr,
   if (DstDevice == HostDevice()) {
     auto Res = SrcDevice->Device->dataRetrieve(DstPtr, SrcPtr, Size, QueueImpl);
     if (Res)
-      return {OL_ERRC_UNKNOWN, "The data retrieve operation failed"};
+      return ol_impl_result_t::fromError(std::move(Res),
+                                         "The data retrieve operation failed");
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RossBrunton wrote:

I've removed the Detail parameter entirely and we just use the Detail from the error message.

https://github.com/llvm/llvm-project/pull/137339