[PATCH] D75835: [X86] Teach combineToExtendBoolVectorInReg to create opportunities for using broadcast load instructions.

[Craig Topper via Phabricator via llvm-commits]

craig.topper created this revision.
craig.topper added reviewers: RKSimon, spatel.
Herald added a subscriber: hiraditya.
Herald added a project: LLVM.

If we're inserting a scalar that is smaller than the element
size of the final VT, the value of the extra bits doesn't matter.

Previously we any_extended in the scalar domain before inserting.

This patch changes this to use a broadcast of the original
scalar type and then a bitcast to the final type. This might
enable the use of a broadcast load.

This recovers regressions from 07d68c24aa19483e44db4336b0935b00a5d69949 <https://reviews.llvm.org/rG07d68c24aa19483e44db4336b0935b00a5d69949>
and 9fcd212e2f678fdbdf304399a1e58ca490dc54d1 <https://reviews.llvm.org/rG9fcd212e2f678fdbdf304399a1e58ca490dc54d1> without relying on
alignment of the load.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D75835

Files:
  llvm/lib/Target/X86/X86ISelLowering.cpp
  llvm/test/CodeGen/X86/bitcast-int-to-vector-bool-sext.ll
  llvm/test/CodeGen/X86/bitcast-int-to-vector-bool-zext.ll
  llvm/test/CodeGen/X86/bitcast-int-to-vector-bool.ll
  llvm/test/CodeGen/X86/vector-sext.ll

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