[all-commits] [llvm/llvm-project] 4a8c13: [CostModel] Add basic fptoi_sat costs

[David Green via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 4a8c13a6f42e9c58af64421790509cc58208859b
      https://github.com/llvm/llvm-project/commit/4a8c13a6f42e9c58af64421790509cc58208859b
  Author: David Green <david.green at arm.com>
  Date:   2022-04-27 (Wed, 27 Apr 2022)

  Changed paths:
    M llvm/include/llvm/CodeGen/BasicTTIImpl.h
    M llvm/test/Analysis/CostModel/AArch64/fptoi_sat.ll
    M llvm/test/Analysis/CostModel/ARM/fptoi_sat.ll
    M llvm/test/Analysis/CostModel/X86/fptoi_sat.ll

  Log Message:
  -----------
  [CostModel] Add basic fptoi_sat costs

This adds some basic fptosi_sat and fptoui_sat target independent cost
modelling. The fptosi_sat is modelled as a fmin/fmax to saturate the
value, followed by a fp convert. The signed values then have an
additional fcmp+select for handling Nan correctly.

The AArch64/Arm costs may be more incorrect, as the instruction exist
natively. This can be fixed with target specific cost updates.

Differential Revision: https://reviews.llvm.org/D124269