[PATCH] D115029: [AArch64] Try to fold lsl + ldr/str

[JinGu Kang via Phabricator via llvm-commits]

jaykang10 created this revision.
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On ISelDAG level, if there are multiple uses of `lsl`, the ldr/str, which are uses of  the `lsl`, are not folded.
Additionaly, if the `lsl` is not in same block with `ldr/str`, they are not folded too.
ldr/str can be folded with `lsl 2` for 32 bit and `lsl 3` for 64 bit as below.

  %7:gpr64 = UBFMXri killed %6:gpr64, 62, 61
  %8:gpr32 = LDRWroX %1:gpr64common, %7:gpr64, 0, 0
  STRWroX killed %9:gpr32, %1:gpr64common, %7:gpr64, 0, 0
  ==>
  %8:gpr32 = LDRWroX %1:gpr64common, %6:gpr64, 0, 1
  STRWroX killed %9:gpr32, %1:gpr64common, %6:gpr64, 0, 1


https://reviews.llvm.org/D115029

Files:
  llvm/lib/Target/AArch64/AArch64MIPeepholeOpt.cpp
  llvm/test/CodeGen/AArch64/aarch64-split-and-bitmask-immediate.ll
  llvm/test/CodeGen/AArch64/extract-bits.ll

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