[all-commits] [llvm/llvm-project] 529bd4: [DAG] SimplifyDemandedBits - don't early-out for m...

[Simon Pilgrim via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 529bd4f3525d7ff564012597df204d8a8a4fb9ac
      https://github.com/llvm/llvm-project/commit/529bd4f3525d7ff564012597df204d8a8a4fb9ac
  Author: Simon Pilgrim <llvm-dev at redking.me.uk>
  Date:   2022-07-27 (Wed, 27 Jul 2022)

  Changed paths:
    M llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
    M llvm/test/CodeGen/AArch64/fptosi-sat-vector.ll
    M llvm/test/CodeGen/AArch64/fptoui-sat-vector.ll
    M llvm/test/CodeGen/AMDGPU/amdgpu-codegenprepare-idiv.ll
    M llvm/test/CodeGen/AMDGPU/cvt_f32_ubyte.ll
    M llvm/test/CodeGen/AMDGPU/local-memory.amdgcn.ll
    M llvm/test/CodeGen/AMDGPU/scalar_to_vector.ll
    M llvm/test/CodeGen/AMDGPU/store-weird-sizes.ll
    M llvm/test/CodeGen/AMDGPU/udiv64.ll
    M llvm/test/CodeGen/AMDGPU/widen-smrd-loads.ll
    M llvm/test/CodeGen/ARM/aes-erratum-fix.ll
    M llvm/test/CodeGen/RISCV/rv32zbp.ll
    M llvm/test/CodeGen/Thumb2/mve-laneinterleaving-cost.ll
    M llvm/test/CodeGen/Thumb2/mve-laneinterleaving.ll
    M llvm/test/CodeGen/Thumb2/mve-sext-masked-load.ll
    M llvm/test/CodeGen/Thumb2/mve-vabdus.ll
    M llvm/test/CodeGen/Thumb2/mve-vmull-splat.ll
    M llvm/test/CodeGen/Thumb2/mve-vst3.ll
    M llvm/test/CodeGen/X86/combine-bitreverse.ll
    M llvm/test/CodeGen/X86/dagcombine-cse.ll
    M llvm/test/CodeGen/X86/hoist-and-by-const-from-shl-in-eqcmp-zero.ll
    M llvm/test/CodeGen/X86/illegal-bitfield-loadstore.ll
    M llvm/test/CodeGen/X86/smul-with-overflow.ll
    M llvm/test/CodeGen/X86/smul_fix_sat_constants.ll
    M llvm/test/CodeGen/X86/srem-seteq-vec-nonsplat.ll
    M llvm/test/CodeGen/X86/urem-seteq-vec-nonsplat.ll

  Log Message:
  -----------
  [DAG] SimplifyDemandedBits - don't early-out for multiple use values

SimplifyDemandedBits currently early-outs for multi-use values beyond the root node (just returning the knownbits), which is missing a number of optimizations as there are plenty of cases where we can still simplify when initially demanding all elements/bits.

@lenary has confirmed that the test cases in aea-erratum-fix.ll need refactoring and the current increase codegen is not a major concern.

Differential Revision: https://reviews.llvm.org/D129765