[clang][NFCI] Fix getGridValues for unsupported targets (#131023)

I broke this in
f3cd223,
I should have added this to the `SPIRV64` subclass, but I accidentally
added it to base `TargetInfo`.

Using an unsupported target should error in the driver way before this
though.

Signed-off-by: Sarnie, Nick <[email protected]>

Author: sarnex

clang/include/clang/Basic/TargetInfo.h

@@ -1675,7 +1675,7 @@ class TargetInfo : public TransferrableTargetInfo,
   // access target-specific GPU grid values that must be consistent between
   // host RTL (plugin), deviceRTL and clang.
   virtual const llvm::omp::GV &getGridValue() const {
-    return llvm::omp::SPIRVGridValues;
+    llvm_unreachable("getGridValue not implemented on this target");
   }
 
   /// Retrieve the name of the platform as it is used in the

clang/lib/Basic/Targets/SPIR.h

@@ -370,6 +370,10 @@ class LLVM_LIBRARY_VISIBILITY SPIRV64TargetInfo : public BaseSPIRVTargetInfo {
 
   void getTargetDefines(const LangOptions &Opts,
                         MacroBuilder &Builder) const override;
+
+  const llvm::omp::GV &getGridValue() const override {
+    return llvm::omp::SPIRVGridValues;
+  }
 };
 
 class LLVM_LIBRARY_VISIBILITY SPIRV64AMDGCNTargetInfo final