[PATCH] D67875: [X86] X86DAGToDAGISel::matchBEXTRFromAndImm(): if can't use BEXTR, fallback to BZHI (PR43381)

[Roman Lebedev via Phabricator via llvm-commits]

lebedev.ri added a comment.

In D67875#1677901 <https://reviews.llvm.org/D67875#1677901>, @davezarzycki wrote:

> If you have the time, the BZHI bits-to-preserve operand only needs MOVB for initialization. That being said, MOVL probably avoids partial register update stalls, so maybe that’s why you’re seeing a performance gain.


Yes, it is intentional to use 32-bit writes to avoid partial register access.


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