[PATCH] D36638: [AVX512] Correct isExtractSubvectorCheap so that it will return true for extracting 128-bits from the upper 256-bits of a 512-bit vector

[Simon Pilgrim via Phabricator via llvm-commits]

RKSimon added a comment.

In https://reviews.llvm.org/D36638#839669, @craig.topper wrote:

> I also wonder if this interface shouldn't take the source type as input. In case some other target has multiple legal vector sizes but can't extract a quarter of vector like x86 can.


+1 for SrcVT as well as ResVT


https://reviews.llvm.org/D36638