[PATCH] D59867: [X86] Teach the isel optimization for (x << C1) op C2 to (x op (C2>>C1)) << C1 to consider cases where C2>>C1 can fit an unsigned 32-bit immediate

[Craig Topper via Phabricator via llvm-commits]

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

For 64-bit operations we should consider if the immediate can be made to fit
in an unsigned 32-bits immedate. For OR/XOR this allows us to load the immediate
with MOV32ri instead of movabsq. For AND this allows us to fold the immediate.


Repository:
  rL LLVM

https://reviews.llvm.org/D59867

Files:
  lib/Target/X86/X86ISelDAGToDAG.cpp
  test/CodeGen/X86/narrow-shl-cst.ll

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