[all-commits] [llvm/llvm-project] e844f0: [LoopUtils] Simplify addRuntimeCheck to return a s...

[Florian Hahn via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: e844f05397b72cbfe20170c445a7dae875df2017
      https://github.com/llvm/llvm-project/commit/e844f05397b72cbfe20170c445a7dae875df2017
  Author: Florian Hahn <flo at fhahn.com>
  Date:   2021-10-18 (Mon, 18 Oct 2021)

  Changed paths:
    M llvm/include/llvm/Transforms/Utils/LoopUtils.h
    M llvm/lib/Transforms/Utils/LoopUtils.cpp
    M llvm/lib/Transforms/Utils/LoopVersioning.cpp
    M llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
    M llvm/test/Transforms/LoopDistribute/basic-with-memchecks.ll
    M llvm/test/Transforms/LoopVectorize/X86/masked_load_store.ll
    M llvm/test/Transforms/LoopVectorize/X86/uniform_mem_op.ll
    M llvm/test/Transforms/LoopVectorize/multiple-strides-vectorization.ll
    M llvm/test/Transforms/LoopVectorize/no_outside_user.ll
    M llvm/test/Transforms/LoopVectorize/pr47343-expander-lcssa-after-cfg-update.ll
    M llvm/test/Transforms/LoopVectorize/pr50686.ll
    M llvm/test/Transforms/LoopVectorize/runtime-check-small-clamped-bounds.ll
    M llvm/test/Transforms/LoopVectorize/skeleton-lcssa-crash.ll
    M llvm/test/Transforms/LoopVersioning/basic.ll
    M llvm/test/Transforms/LoopVersioning/lcssa.ll

  Log Message:
  -----------
  [LoopUtils] Simplify addRuntimeCheck to return a single value.

This simplifies the return value of addRuntimeCheck from a pair of
instructions to a single `Value *`.

The existing users of addRuntimeChecks were ignoring the first element
of the pair, hence there is not reason to track FirstInst and return
it.

Additionally all users of addRuntimeChecks use the second returned
`Instruction *` just as `Value *`, so there is no need to return an
`Instruction *`. Therefore there is no need to create a redundant
dummy `and X, true` instruction any longer.

Effectively this change should not impact the generated code because the
redundant AND will be folded by later optimizations. But it is easy to
avoid creating it in the first place and it allows more accurately
estimating the cost of the runtime checks.