Builtins Implementation Status compared to LLVM

[NandniJamnadas]

This issue was also raised in CORE-V LLVM openhwgroup/corev-llvm-project#60, where some builtins test fails due to implementation in either CORE-V GCC or CORE-V LLVM.

[MaryBennett]

Is the difference in the mac extension due to the builtin being mixed case in LLVM but lower case in GCC?

No, the problem is that LLVM does not have mac builtins.

[MaryBennett]

cv-simd-{extract/extractu/insert/sll/sra/srl}-* tests require review against the spec.

[MaryBennett]

Action:

1. @MaryBennett review LLVM/GCC to find differences and record here