[PATCH] D35319: LSE Atomics reorg - Part I

[Stefan Teleman via Phabricator via llvm-commits]

steleman added a comment.

It does not appear that the multiclass design you are advocating here does what we'd expect it to do.

For one of the simple LD<OP> atomics - namely LDADD - I have placed a test program with corresponding output here:

1. lseadd.c - https://drive.google.com/open?id=0B9ulXWgBcdxxcDNmNU1yVnQ5aXM
2. lseadd.sh - https://drive.google.com/open?id=0B9ulXWgBcdxxTHI2MXd6dTZ0aVk
3. lseadd-clang-O2.S - https://drive.google.com/open?id=0B9ulXWgBcdxxUW0yVEJCeE9mUTQ
4. lseadd-clang-O2.ll - https://drive.google.com/open?id=0B9ulXWgBcdxxOTZRNjl6b1drVGM

The contents of these files is pretty self-explanatory.

Description of the problem: regardless of the atomic ordering model chosen in the test program -- in this case it's __ATOMIC_SEQ_CST -- TableGen will always match to **ldadd**, which is incorrect, instead of **ldaddal**, which is what would be expected in this case. This is shown in the lseadd-clang-O2.S assembler file indicated above.

However, the LLVM IR output matches the atomic ordering correctly.

The problem disappears and the matching is performed correctly if the Pats are explicitly written in the AArch64InstrAtomics.td file.


Repository:
  rL LLVM

https://reviews.llvm.org/D35319