[llvm-dev] Pattern transformation between scalar and vector on IR.
Jojo Ma via llvm-dev
llvm-dev at lists.llvm.org
Thu Sep 8 02:32:17 PDT 2016
I'm tring to use RSQRT instructions on follow case for ARM
(now what using is sqrt):
1.0 / sqrt(x)
The RSQRT instructions(VRSQRTE/VRSQRTS) are vector type,
but above operation is scalar type. So a transformation must be
done(transform sqrt pattern to rsqrt).
I have completed a patch for this, but I made the transformation in the
backend which will leads to additional latencies.And actually it's not
reasonable doing transformation in backend.
I think it would be better done that on IR. I am a novice to llvm.I don't
know anything about this subject. If anyone could
give me some advice would be appreciated.
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