[llvm] [Offload] Don't add the unsupported host plugin to the list (PR #159642)

[Joseph Huber via llvm-commits]

https://github.com/jhuber6 created https://github.com/llvm/llvm-project/pull/159642

Summary:
The host plugin is basically OpenMP specific and doesn't work very well.
Previously we were skipping over it in the list instead of just not
adding it at all.


>From ffabde279cf64cf281735dc313eeb2f49fc52a4e Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Thu, 18 Sep 2025 14:58:52 -0500
Subject: [PATCH] [Offload] Don't add the unsupported host plugin to the list

Summary:
The host plugin is basically OpenMP specific and doesn't work very well.
Previously we were skipping over it in the list instead of just not
adding it at all.
---
 offload/liboffload/src/OffloadImpl.cpp | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/offload/liboffload/src/OffloadImpl.cpp b/offload/liboffload/src/OffloadImpl.cpp
index b5b9b0e83b975..bf220779180c5 100644
--- a/offload/liboffload/src/OffloadImpl.cpp
+++ b/offload/liboffload/src/OffloadImpl.cpp
@@ -244,17 +244,15 @@ Error initPlugins(OffloadContext &Context) {
   // Attempt to create an instance of each supported plugin.
 #define PLUGIN_TARGET(Name)                                                    \
   do {                                                                         \
-    Context.Platforms.emplace_back(ol_platform_impl_t{                         \
-        std::unique_ptr<GenericPluginTy>(createPlugin_##Name()),               \
-        pluginNameToBackend(#Name)});                                          \
+    if (StringRef(#Name) != "host")                                            \
+      Context.Platforms.emplace_back(ol_platform_impl_t{                       \
+          std::unique_ptr<GenericPluginTy>(createPlugin_##Name()),             \
+          pluginNameToBackend(#Name)});                                        \
   } while (false);
 #include "Shared/Targets.def"
 
   // Preemptively initialize all devices in the plugin
   for (auto &Platform : Context.Platforms) {
-    // Do not use the host plugin - it isn't supported.
-    if (Platform.BackendType == OL_PLATFORM_BACKEND_UNKNOWN)
-      continue;
     auto Err = Platform.Plugin->init();
     [[maybe_unused]] std::string InfoMsg = toString(std::move(Err));
     for (auto DevNum = 0; DevNum < Platform.Plugin->number_of_devices();