David Sherwood 652faed353 [CodeGen] Improve SelectionDAGBuilder lowering code for get.active.lane.mask intrinsic ...

Previously we were using UADDO to generate a two-result value with
the unsigned addition and the overflow mask. We then combined the
overflow mask with the trip count comparison to get a result.
However, we don't need to do this - we can simply use a UADDSAT
saturating add node to add the vector index splat and the stepvector
together. Then we can just compare this to a splat of the trip count.
This results in overall better code quality for both Thumb2 and AArch64.

Differential Revision: https://reviews.llvm.org/D115354

2021-12-10 13:39:38 +00:00

8.3 KiB

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