[PATCH] D65904: [X86] Allow pack instructions to be used for 512->256 truncates when -mprefer-vector-width=256 is causing 512-bit vectors to be split

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.
craig.topper added reviewers: spatel, RKSimon.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.

If we're splitting the 512-bit vector anyway and we have zero/sign bits, then we might as well use pack instructions to concat and truncate at once.


https://reviews.llvm.org/D65904

Files:
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/test/CodeGen/X86/min-legal-vector-width.ll

-------------- next part --------------
A non-text attachment was scrubbed...
Name: D65904.213989.patch
Type: text/x-patch
Size: 5292 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20190807/ca48d7b2/attachment.bin>