afec08ef9f
Fixes https://github.com/llvm/llvm-project/issues/53520. #### Description #### Provide `intrin0.h` to be the minimal set of intrinsics that the MSVC STL requires. The `intrin0.h` header matches the latest header provided by MSVC 1939 which does include some extra intrinsics that the MSVC STL does not use. Inside `BuiltinHeaders.def` I kept the header description as `intrin.h`. If you want me to change those to `intrin0.h` for the moved intrinsics let me know. This should now allow `immintrin.h` to be used with function targets for runtime cpu detection of simd instruction sets without worrying about the compile-time overhead from MSVC STL including `intrin.h` on clang. I still need to figure out how to best update MSVC STL to detect for the presence of `intrin0.h` from clang and to use this header over `intrin.h`. #### Testing #### Built clang locally and ran the test suite. I still need to do a pass over the existing unit tests for the ms intrinsics to make sure there aren't any gaps. Wanted to get this PR up for discussion first. Modified latest MSVC STL from github to point to `intrin0.h` for clang. Wrote some test files that included MSVC STL headers that rely on intrinsics such as `atomic`, `bit` and `vector`. Built the unit tests against x86, arm, aarch64, and x64. #### Benchmarks #### The following include times are based on the x64 target with the modified headers in this PR. These timings were done by using `clang-cl.exe -ftime-trace` and taking the wall time for parsing `intrin.h` and `intrin0.h`. `intrin.h` takes ~897ms to parse. `intrin0.h` takes ~1ms to parse. If there is anything required or a different approach is preferred let me know. I would very much like to move this over the finish line so we can use function targets with clang-cl.
26 lines
687 B
C
26 lines
687 B
C
//===----- yvals_core.h - Internal MSVC STL core header -------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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// Only include this if we are aiming for MSVC compatibility.
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#ifndef _MSC_VER
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#include_next <yvals_core.h>
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#else
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#ifndef __clang_yvals_core_h
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#define __clang_yvals_core_h
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#include_next <yvals_core.h>
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#ifdef _STL_INTRIN_HEADER
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#undef _STL_INTRIN_HEADER
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#define _STL_INTRIN_HEADER <intrin0.h>
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#endif
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#endif
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#endif
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