[all-commits] [llvm/llvm-project] f7907e: [TRE] allow TRE for non-capturing calls.

[avl-llvm via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: f7907e9d223d8484f9afd457ba614c2db2ae4743
      https://github.com/llvm/llvm-project/commit/f7907e9d223d8484f9afd457ba614c2db2ae4743
  Author: Alexey Lapshin <a.v.lapshin at mail.ru>
  Date:   2020-07-11 (Sat, 11 Jul 2020)

  Changed paths:
    M llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
    M llvm/test/Transforms/TailCallElim/basic.ll
    A llvm/test/Transforms/TailCallElim/tre-multiple-exits.ll
    A llvm/test/Transforms/TailCallElim/tre-noncapturing-alloca-calls.ll

  Log Message:
  -----------
  [TRE] allow TRE for non-capturing calls.

The current implementation of Tail Recursion Elimination has a very restricted
pre-requisite: AllCallsAreTailCalls. i.e. it requires that no function
call receives a pointer to local stack. Generally, function calls that
receive a pointer to local stack but do not capture it - should not
break TRE. This fix allows us to do TRE if it is proved that no pointer
to the local stack is escaped.

Reviewed by: efriedma

Differential Revision: https://reviews.llvm.org/D82085