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[X86] Move splat addends from the gather/scatter index operand to the base address
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Authored by pengfei on Mon, Oct 11, 6:32 PM.



This can avoid a vector add and a constant pool load. Or an explicit broadcast in case of non-constant.

Also reverse the transform any time we encounter a constant index addend that can't be moved to base. In that case pull the constant from base into the index. This reduces code size needed for the displacement since we needed the index add anyway. Limit this to scale of 1 to avoid divisibility and wrap issues.

Authored by Craig.

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Event Timeline

pengfei created this revision.Mon, Oct 11, 6:32 PM
pengfei requested review of this revision.Mon, Oct 11, 6:32 PM
Herald added a project: Restricted Project. · View Herald TranscriptMon, Oct 11, 6:32 PM
craig.topper added inline comments.Wed, Oct 13, 9:33 AM

Please run clang-format


"gather scatter" -> "gather/scatter" or "gather or scatter"


Drop the comma after possible.

"case case" -> "case,"

pengfei updated this revision to Diff 379569.Wed, Oct 13, 5:40 PM
pengfei marked 3 inline comments as done.

Address review comments. Thanks Craig.