[all-commits] [llvm/llvm-project] b0daac: [CodeGen] Use llvm::bit_ceil (NFC)

[kazutakahirata via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: b0daacf58f417634f7c7c9496589d723592a8f5a
      https://github.com/llvm/llvm-project/commit/b0daacf58f417634f7c7c9496589d723592a8f5a
  Author: Kazu Hirata <kazu at google.com>
  Date:   2023-01-24 (Tue, 24 Jan 2023)

  Changed paths:
    M clang/lib/CodeGen/SwiftCallingConv.cpp

  Log Message:
  -----------
  [CodeGen] Use llvm::bit_ceil (NFC)

If we know that x is nonzero and not a power of 2, then
llvm::findLastSet(x) + 1 is the index of the bit just above the
highest set bit in x.  That is, 1 << (llvm::findLastSet(x) + 1) is the
same as llvm::bit_ceil(x).

Since llvm::bit_ceil is a nop on a power of 2, we can unconditionally
call llvm::bit_ceil.  The end result actually matches the comment.