[PATCH] D54710: [x86] don't try to convert add with undef operands to LEA

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a comment.

In D54710#1319436 <https://reviews.llvm.org/D54710#1319436>, @aemerson wrote:

>   This seems to me to be a bug in ProcessImplicitDefs, for some reasoning killing the IMPLICIT_DEF even though there's a subreg use. GlobalISel MIR output looks fine to me.


Regardless of whether there's a bug in ProcessImplicitDefs, we would have to correctly propagate the undef flag through this transform (from 'add' to 'lea') though? I'm proposing to avoid that for this case based on existing code that appears to do the same thing.


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