[PATCH] D73073: AMDGPU: Add option to expand 64-bit integer division in IR

[Matt Arsenault via Phabricator via llvm-commits]

arsenm created this revision.
arsenm added a reviewer: rampitec.
Herald added subscribers: kerbowa, hiraditya, t-tye, tpr, dstuttard, yaxunl, nhaehnle, wdng, jvesely, kzhuravl.
Herald added a project: LLVM.

I didn't realize we were already expanding 24/32-bit division here
already. Use the available IntegerDivision utilities. This uses loops,
so produces significantly smaller code than the inline DAG expansion.

      

This now requires width reductions of 64-bit divisions before
introducing the expanded loops.

      

This helps work around missing legalization in GlobalISel for
division, which are the only remaining core instructions that didn't
work at all.

I think this is plausibly a better implementation than exists in the
DAG, although turning it on by default misses out on the constant
value optimizations and also needs benchmarking.


https://reviews.llvm.org/D73073

Files:
  llvm/lib/Target/AMDGPU/AMDGPUCodeGenPrepare.cpp
  llvm/test/CodeGen/AMDGPU/sdiv64.ll
  llvm/test/CodeGen/AMDGPU/srem64.ll
  llvm/test/CodeGen/AMDGPU/udiv64.ll
  llvm/test/CodeGen/AMDGPU/urem64.ll

-------------- next part --------------
A non-text attachment was scrubbed...
Name: D73073.239215.patch
Type: text/x-patch
Size: 264653 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20200121/f084d71d/attachment-0001.bin>