[clang] [llvm] [LLVM][Triple][NFCI] Add function to test for GPU offloading triples (PR #126956)

[Shilei Tian via cfe-commits]

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@@ -1109,6 +1109,11 @@ class Triple {
            Env == llvm::Triple::EABIHF;
   }
 
+  /// Tests if the target represents a GPU which can be offloaded to.
+  bool isOffloadingTargetGPU() const {
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shiltian wrote:

Is it better to use `isOffloadingTarget`?

https://github.com/llvm/llvm-project/pull/126956