[LLVMdev] vselect on ARM/NEON
peter.couperus at st.com
Fri Oct 12 08:03:53 PDT 2012
Thanks for the comments. I'll submit the one-line patch, with a
simplified testcase from one of the PRs shortly.
On 10/11/2012 11:48 AM, Nadav Rotem wrote:
> If you mark VSELECT as 'expand' then it will be expanded to a sequence of AND/OR/XOR, which is pretty efficient (found in LegalizeVectorOps.cpp ExpandVSELECT).
> On Oct 11, 2012, at 11:05 AM, Jim Grosbach<grosbach at apple.com> wrote:
>> Seems reasonable to me. Plain 'SELECT' is already marked expand for vector types. I bet that just didn't get updates when VSELECT was introduced.
>> On Oct 11, 2012, at 10:25 AM, Peter Couperus<peter.couperus at st.com> wrote:
>>> We've run into a couple of cases where we'd like to use select on vector types, but vselect handling is absent from the ARM backend.
>>> Would there be any potential harm by marking VSELECT as Expand on ARM targets with NEON?
>>> Adding this seems to fix the following PR's:
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>>> LLVMdev at cs.uiuc.edu http://llvm.cs.uiuc.edu
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