[all-commits] [llvm/llvm-project] 1768cb: Use __builtin_clz to find leading 1 in generic sqr...

[Clint Caywood via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 1768cb3a674ad657dd3eccd001f0a3e9a7675af6
      https://github.com/llvm/llvm-project/commit/1768cb3a674ad657dd3eccd001f0a3e9a7675af6
  Author: Clint Caywood <clint at clintcaywood.com>
  Date:   2022-02-28 (Mon, 28 Feb 2022)

  Changed paths:
    M libc/src/__support/FPUtil/generic/sqrt.h
    M libc/src/__support/FPUtil/generic/sqrt_80_bit_long_double.h

  Log Message:
  -----------
  Use __builtin_clz to find leading 1 in generic sqrt (where possible)

__builtin_clz requires just a single instruction on x86 and arm, so this is a performance improvement.

Reviewed By: lntue

Differential Revision: https://reviews.llvm.org/D120579