[all-commits] [llvm/llvm-project] da81ec: [SimplifyCFG] Volatile memory operations do not trap

[Roman Lebedev via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: da81ec61585b717d7f0c07aa3e2b5460eeeb6ce3
      https://github.com/llvm/llvm-project/commit/da81ec61585b717d7f0c07aa3e2b5460eeeb6ce3
  Author: Roman Lebedev <lebedev.ri at gmail.com>
  Date:   2021-07-02 (Fri, 02 Jul 2021)

  Changed paths:
    M llvm/lib/Transforms/Utils/SimplifyCFG.cpp
    M llvm/test/Transforms/SimplifyCFG/trapping-load-unreachable.ll

  Log Message:
  -----------
  [SimplifyCFG] Volatile memory operations do not trap

Somewhat related to D105338.
While it is up for discussion whether or not volatile store traps,
so far there has been no complaints that volatile load/cmpxchg/atomicrmw also may trap.
And even if simplifycfg currently concervatively believes that to be the case,
instcombine does not: https://godbolt.org/z/5vhv4K5b8

Reviewed By: nikic

Differential Revision: https://reviews.llvm.org/D105343