[all-commits] [llvm/llvm-project] 3ddf56: [Statepoint] Use default attributes for some GC in...

[Nikita Popov via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 3ddf56fd37b863bd778a63339e7c1ad9eca789d9
      https://github.com/llvm/llvm-project/commit/3ddf56fd37b863bd778a63339e7c1ad9eca789d9
  Author: Nikita Popov <npopov at redhat.com>
  Date:   2022-11-08 (Tue, 08 Nov 2022)

  Changed paths:
    M llvm/include/llvm/IR/Intrinsics.td
    M llvm/test/Transforms/RewriteStatepointsForGC/statepoint-attrs.ll

  Log Message:
  -----------
  [Statepoint] Use default attributes for some GC intrinsics

This adds the default intrinsic attributes (nosync, nofree, nocallback,
willreturn) to the gc.result, gc.relocate, gc.pointer.base and
gc.pointer.offset intrinsics. As far as I understand, all of these
are supposed to be pure. Some quotes from LangRef:

> A gc.result is modeled as a ‘readnone’ pure function. It has no
> side effects since it is just a projection of the return value of
> the previous call represented by the gc.statepoint.

> A gc.relocate is modeled as a readnone pure function. It has no
> side effects since it is just a way to extract information about
> work done during the actual call modeled by the gc.statepoint.

Having willreturn in particular will be important to avoid
optimization regressions in the future.

Differential Revision: https://reviews.llvm.org/D136929