[clang] [flang] [mlir] [flang] Add basic -mtune support (PR #95043)

[Andrzej Warzyński via cfe-commits]

banach-space wrote:

> LLVM Buildbot has detected a new failure on builder `flang-aarch64-libcxx` running on `linaro-flang-aarch64-libcxx` while building `clang,flang,mlir` at step 6 "test-build-unified-tree-check-flang".
> 
> Full details are available at: https://lab.llvm.org/buildbot/#/builders/89/builds/791
> 
> Here is the relevant piece of the build log for the reference:
> 
> ```
> Step 6 (test-build-unified-tree-check-flang) failure: test (failure)
> ******************** TEST 'Flang :: Lower/tune-cpu-llvm.f90' FAILED ********************
> Exit Code: 2
> 
> Command Output (stderr):
> --
> RUN: at line 1: /home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/bin/flang-new -mtune=pentium4 -S -emit-llvm /home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/flang/test/Lower/tune-cpu-llvm.f90 -o - | /home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/bin/FileCheck /home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/flang/test/Lower/tune-cpu-llvm.f90
> + /home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/bin/flang-new -mtune=pentium4 -S -emit-llvm /home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/flang/test/Lower/tune-cpu-llvm.f90 -o -
> + /home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/bin/FileCheck /home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/flang/test/Lower/tune-cpu-llvm.f90
> flang-new: error: unsupported argument 'pentium4' to option '-mtune='
> FileCheck error: '<stdin>' is empty.
> FileCheck command line:  /home/tcwg-buildbot/worker/flang-aarch64-libcxx/build/bin/FileCheck /home/tcwg-buildbot/worker/flang-aarch64-libcxx/llvm-project/flang/test/Lower/tune-cpu-llvm.f90
> 
> --
> 
> ********************
> ```

Most likely https://github.com/llvm/llvm-project/pull/95043/files#diff-a29a79ef4763ed66987d979a7a8a4ff87d242101fe133d5188577b9ff144b805 requires X86 to be enabled. Could somebody either fix or revert? I don’t have access to Git ATM.

https://github.com/llvm/llvm-project/pull/95043