[i386] Modify the alignment of __m128/__m256/__m512 vector type according i386 abi.
According to i386 System V ABI:
1. when __m256 are required to be passed on the stack, the stack pointer must be aligned on a 0 mod 32 byte boundary at the time of the call.
2. when __m512 are required to be passed on the stack, the stack pointer must be aligned on a 0 mod 64 byte boundary at the time of the call.
The current method of clang passing __m512 parameter are as follow:
1. when target supports avx512, passing it with 64 byte alignment;
2. when target supports avx, passing it with 32 byte alignment;
3. Otherwise, passing it with 16 byte alignment.
Passing __m256 parameter are as follow:
1. when target supports avx or avx512, passing it with 32 byte alignment;
2. Otherwise, passing it with 16 byte alignment.
This pach will passing __m128/__m256/__m512 following i386 System V ABI and
apply it to Linux only since other System V OS (e.g Darwin, PS4 and FreeBSD) don't
want to spend any effort dealing with the ramifications of ABI breaks at present.
Differential Revision: https://reviews.llvm.org/D78564
GitOrigin-RevId: 1c4108ab661d43e21b1d1c804d8a403e5b0cf7d6
2 files changed
