[PATCH] D67614: [ARM] SBFX from rsb patterns

[Dave Green via Phabricator via llvm-commits]

dmgreen created this revision.
dmgreen added reviewers: t.p.northover, SjoerdMeijer, samparker, ostannard, efriedma.
Herald added subscribers: hiraditya, kristof.beyls.
Herald added a project: LLVM.

Sometimes ISel will generate RSB patterns for sequences that should be transformed into sbfx, instead of the usual shifts, and we end up generating a RSB and a UBFX. This adds some extra patterns to catch the other cases. The existing sbfx patterns are selected through ARMDAGToDAGISel::tryV6T2BitfieldExtractOp, but these tablegen patterns seem to work for these cases just fine. Helps especially in the MVE predication code.


https://reviews.llvm.org/D67614

Files:
  llvm/lib/Target/ARM/ARMInstrThumb2.td
  llvm/test/CodeGen/ARM/sbfx.ll
  llvm/test/CodeGen/Thumb2/bfx.ll
  llvm/test/CodeGen/Thumb2/mve-masked-ldst.ll
  llvm/test/CodeGen/Thumb2/mve-pred-bitcast.ll
  llvm/test/CodeGen/Thumb2/mve-pred-build-var.ll
  llvm/test/CodeGen/Thumb2/mve-pred-ext.ll
  llvm/test/CodeGen/Thumb2/mve-pred-loadstore.ll

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