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1. The PR proceeds with a backend target hook to allow front-ends to determine what target features are available in a compilation based on the CPU name. 2. Fix a backend target feature bug that supports HTM for Power8/9/10/11. However, HTM is only supported on Power8/9 according to the ISA. 3. All target features that are hardcoded in PPC.cpp can be retrieved from the backend target feature. I have double-checked that the hardcoded logic for inferring target features from the CPU in the frontend(PPC.cpp) is the same as in PPC.td. The reland patch addressed the comment https://github.com/llvm/llvm-project/pull/137670#discussion_r2143541120