llvm-project

Commit Graph

Author	SHA1	Message	Date
Siva Chandra Reddy	7cd420649f	[libc][NFC] Use a end of list marker for cpu feature detection. Without this, the array can end up being an empty array leading to compiler failures.	2021-01-27 01:24:15 -08:00
Guillaume Chatelet	04a309dd0b	[libc] Adding memcpy implementation for x86_64 Summary: The patch is not ready yet and is here to discuss a few options: - How do we customize the implementation? (i.e. how to define `kRepMovsBSize`), - How do we specify custom compilation flags? (We'd need `-fno-builtin-memcpy` to be passed in), - How do we build? We may want to test in debug but build the libc with `-march=native` for instance, - Clang has a brand new builtin `__builtin_memcpy_inline` which makes the implementation easy and efficient, but: - If we compile with `gcc` or `msvc` we can't use it, resorting on less efficient code generation, - With gcc we can use `__builtin_memcpy` but then we'd need a postprocess step to check that the final assembly do not contain call to `memcpy` (unlikely but allowed), - For msvc we'd need to resort on the compiler optimization passes. Reviewers: sivachandra, abrachet Subscribers: mgorny, MaskRay, tschuett, libc-commits, courbet Tags: #libc-project Differential Revision: https://reviews.llvm.org/D74397	2020-03-18 17:43:21 +01:00
Guillaume Chatelet	1aab055dd8	[libc] Add CMake script to check host cpu features Summary: Tested on MacOSX and Linux. For robustness we can go the OpenCV way and add individual c++ files with intrinsics. https://github.com/opencv/opencv/blob/master/cmake/checks/cpu_avx2.cpp Reviewers: sivachandra, abrachet Subscribers: mgorny, MaskRay, tschuett, libc-commits Tags: #libc-project Differential Revision: https://reviews.llvm.org/D74897	2020-02-27 09:52:26 +01:00

Author

SHA1

Message

Date

Siva Chandra Reddy

7cd420649f

[libc][NFC] Use a end of list marker for cpu feature detection.

Without this, the array can end up being an empty array leading to
compiler failures.

2021-01-27 01:24:15 -08:00

Guillaume Chatelet

04a309dd0b

[libc] Adding memcpy implementation for x86_64

Summary:
The patch is not ready yet and is here to discuss a few options:
 - How do we customize the implementation? (i.e. how to define `kRepMovsBSize`),
 - How do we specify custom compilation flags? (We'd need `-fno-builtin-memcpy` to be passed in),
 - How do we build? We may want to test in debug but build the libc with `-march=native` for instance,
 - Clang has a brand new builtin `__builtin_memcpy_inline` which makes the implementation easy and efficient, but:
   - If we compile with `gcc` or `msvc` we can't use it, resorting on less efficient code generation,
   - With gcc we can use `__builtin_memcpy` but then we'd need a postprocess step to check that the final assembly do not contain call to `memcpy` (unlikely but allowed),
   - For msvc we'd need to resort on the compiler optimization passes.

Reviewers: sivachandra, abrachet

Subscribers: mgorny, MaskRay, tschuett, libc-commits, courbet

Tags: #libc-project

Differential Revision: https://reviews.llvm.org/D74397

2020-03-18 17:43:21 +01:00

Guillaume Chatelet

1aab055dd8

[libc] Add CMake script to check host cpu features

Summary:
Tested on MacOSX and Linux.
For robustness we can go the OpenCV way and add individual c++ files with intrinsics.
https://github.com/opencv/opencv/blob/master/cmake/checks/cpu_avx2.cpp

Reviewers: sivachandra, abrachet

Subscribers: mgorny, MaskRay, tschuett, libc-commits

Tags: #libc-project

Differential Revision: https://reviews.llvm.org/D74897

2020-02-27 09:52:26 +01:00

3 Commits