tree 28d0266b52541483832f536a8bc5e3f974ac47e9
parent 8b5527deefdfcb7a2ea90b9b4d2116864e7d493f
author Ahmed Bougacha <ahmed.bougacha@gmail.com> 1425345676 +0000
committer Ahmed Bougacha <ahmed.bougacha@gmail.com> 1425345676 +0000

[X86] Special-case 2x CMOV when custom-inserting.

This lets us avoid a few copies that are otherwise hard to get rid of.
The way this is done is, the custom-inserter looks at the following
instruction for another CMOV, and replaces both at the same time.
A previous version used a new CMOV2 opcode, but the custom inserter
is expected to be able to return a different basic block anyway, which
means it's OK - though far from ideal - to alter that block's contents.
Explicitly document that, in case it ever makes a difference.
Alternatives welcome!

Follow-up to r231045.

rdar://19767934
Closes http://reviews.llvm.org/D8019


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@231046 91177308-0d34-0410-b5e6-96231b3b80d8