[llvm] [Xtensa] Initial codegen support from IR (PR #78548)

[Sergei Barannikov via llvm-commits]

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@@ -36,10 +37,15 @@ class XtensaTargetMachine : public LLVMTargetMachine {
                       std::optional<CodeModel::Model> CM, CodeGenOptLevel OL,
                       bool JIT);
 
+  const XtensaSubtarget *getSubtargetImpl() const { return &Subtarget; }
+  const XtensaSubtarget *getSubtargetImpl(const Function &F) const override;
   TargetPassConfig *createPassConfig(PassManagerBase &PM) override;
   TargetLoweringObjectFile *getObjFileLowering() const override {
     return TLOF.get();
   }
+
+protected:
+  XtensaSubtarget Subtarget;
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s-barannikov wrote:

See the comment above, there should be no "default" subtarget.

https://github.com/llvm/llvm-project/pull/78548