[PATCH] D119469: [AArch64] Turn truncating buildvectors into truncates

Wed Feb 16 01:30:59 PST 2022

dmgreen added a comment.

In D119469#3323751 <https://reviews.llvm.org/D119469#3323751>, @efriedma wrote:

>> creating an illegal v4i8 concat that gets expanded into a BUILD_VECTOR
>
> Maybe it would make sense to stop this from happening?  concat_vectors where the operands will be widened seems like it would be a common pattern.

Yeah - That is something I looked into, but didn't get very far as it seems simple enough to fix after. That seems to be the same way we handle all other concats - we expand them with extract then reconstruct the shuffle. I think it would be a too large job to try and change how concat is lowered.

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D119469/new/

https://reviews.llvm.org/D119469