[all-commits] [llvm/llvm-project] bbe16b: [ARM] Transform a fixed-point to floating-point co...

[Sam Tebbs via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: bbe16b7af2d66d2abcf75ad72af6155d4da964cb
      https://github.com/llvm/llvm-project/commit/bbe16b7af2d66d2abcf75ad72af6155d4da964cb
  Author: Sam Tebbs <samuel.tebbs at arm.com>
  Date:   2021-06-21 (Mon, 21 Jun 2021)

  Changed paths:
    M llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
    A llvm/test/CodeGen/Thumb2/mve-vcvt-fixed.ll

  Log Message:
  -----------
  [ARM] Transform a fixed-point to floating-point conversion into a VCVT_fix

Conversion from a fixed-point number to a floating-point number is done by
multiplying the fixed-point number by 2^(-n) where n is the number of
fractional bits. Currently this is lowered to a vcvt
(integer to floating-point) then a vmul, but it can instead be lowered
directly to a vcvt (fixed-point to floating-point). This patch enables
such transformations as long as the multiplication factor is a power of 2.

Differential Revision: https://reviews.llvm.org/D103903