[all-commits] [llvm/llvm-project] f62c92: [LoongArch] Support -march=native and -mtune=

[Lu Weining via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: f62c9252fc0f1fa0a0f02033659db052c2202a4c
      https://github.com/llvm/llvm-project/commit/f62c9252fc0f1fa0a0f02033659db052c2202a4c
  Author: Weining Lu <luweining at loongson.cn>
  Date:   2023-08-09 (Wed, 09 Aug 2023)

  Changed paths:
    M clang/lib/Basic/Targets/LoongArch.cpp
    M clang/lib/Basic/Targets/LoongArch.h
    M clang/lib/Driver/ToolChains/Arch/LoongArch.cpp
    M clang/lib/Driver/ToolChains/Arch/LoongArch.h
    M clang/lib/Driver/ToolChains/Clang.cpp
    M clang/lib/Driver/ToolChains/CommonArgs.cpp
    M clang/test/Driver/loongarch-march-error.c
    M clang/test/Driver/loongarch-march.c
    A clang/test/Driver/loongarch-mtune.c
    M clang/test/Preprocessor/init-loongarch.c
    M llvm/include/llvm/TargetParser/LoongArchTargetParser.h
    M llvm/lib/Target/LoongArch/LoongArch.td
    M llvm/lib/TargetParser/LoongArchTargetParser.cpp
    A llvm/test/CodeGen/LoongArch/cpus-invalid.ll
    A llvm/test/CodeGen/LoongArch/cpus.ll

  Log Message:
  -----------
  [LoongArch] Support -march=native and -mtune=

As described in [1][2], `-mtune=` is used to select the type of target
microarchitecture, defaults to the value of `-march`. The set of
possible values should be a superset of `-march` values. Currently
possible values of `-march=` and `-mtune=` are `native`, `loongarch64`
and `la464`.

D136146 has supported `-march={loongarch64,la464}` and this patch adds
support for `-march=native` and `-mtune=`.

A new ProcessorModel called `loongarch64` is defined in LoongArch.td
to support `-mtune=loongarch64`.

`llvm::sys::getHostCPUName()` returns `generic` on unknown or future
LoongArch CPUs, e.g. the not yet added `la664`, leading to
`llvm::LoongArch::isValidArchName()` failing to parse the arch name.
In this case, use `loongarch64` as the default arch name for 64-bit
CPUs.

Two preprocessor macros are defined based on user-provided `-march=`
and `-mtune=` options and the defaults.
- __loongarch_arch
- __loongarch_tune
Note that, to work with `-fno-integrated-cc1` we leverage cc1 options
`-target-cpu` and `-tune-cpu` to pass driver options `-march=` and
`-mtune=` respectively because cc1 needs these information to define
macros in `LoongArchTargetInfo::getTargetDefines`.

[1]: https://github.com/loongson/LoongArch-Documentation/blob/2023.04.20/docs/LoongArch-toolchain-conventions-EN.adoc
[2]: https://github.com/loongson/la-softdev-convention/blob/v0.1/la-softdev-convention.adoc

Reviewed By: xen0n, wangleiat, steven_wu, MaskRay

Differential Revision: https://reviews.llvm.org/D155824