[PATCH] D120571: [CGP, AArch64] Replace zexts with shuffle that can be lowered using tbl.

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.
Herald added a subscriber: StephenFan.

Regression reported at https://github.com/llvm/llvm-project/issues/62620 .  I think the issue is that this transform isn't aware of widening instructions; if the <16 x i32> output is used in a way that can be optimized to use 16-bit inputs, the six ushll/ushll2 instructions are actually lowered to just two ushll/ushll2 instructions, so transforming that into for tbl isn't profitable.


Repository:
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https://reviews.llvm.org/D120571