[PATCH] D48278: [SelectionDAG] Fold redundant masking operations of shifted value

[Sanjay Patel via Phabricator via llvm-commits]

spatel requested changes to this revision.
spatel added reviewers: craig.topper, RKSimon, lebedev.ri.
spatel added a comment.
This revision now requires changes to proceed.

This patch was reverted with https://reviews.llvm.org/rL336453 because it caused:
https://bugs.llvm.org/show_bug.cgi?id=38084

Beyond that, I don't understand the motivation. The patch increases the latency of a computation. Why is that beneficial? The x86 diff doesn't look like a win to me.

I don't know what the ARM/AArch output looked like before this patch. Always check in the baseline tests before making a code change, so we have that as a reference (and in case the patch is reverted, we won't lose the test coverage that motivated the code patch).


https://reviews.llvm.org/D48278