[PATCH] D47346: [X86] Add a new pass to fold extension into load instructions in previous BB

[Guozhi Wei via Phabricator via llvm-commits]

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In https://reviews.llvm.org/D47346#1111861, @chandlerc wrote:

> We have an MI combine pass IIRC -- why not put this there? (Genuine question, haven't looked at these enough to know if that doesn't work...)


The patterns handled by MachineCombiner usually are simple code sequences in a single basic block, new code sequences are inserted at the root instruction. The pattern handled by this file may cross several basic blocks, new instructions are inserted at multiple positions in previous basic blocks. So it can't be handled by MachineCombiner.


https://reviews.llvm.org/D47346