[all-commits] [llvm/llvm-project] 42e88b: Replace sequences of v.push_back(v[i]); v.erase(&v...

[Mehdi Amini via All-commits]

  Branch: refs/heads/master
  Home:   https://github.com/llvm/llvm-project
  Commit: 42e88bd6b18597fe0a46ee9663d4e2cf2f7a4e57
      https://github.com/llvm/llvm-project/commit/42e88bd6b18597fe0a46ee9663d4e2cf2f7a4e57
  Author: Mehdi Amini <joker.eph at gmail.com>
  Date:   2020-11-14 (Sat, 14 Nov 2020)

  Changed paths:
    M clang/lib/CodeGen/CGBuiltin.cpp

  Log Message:
  -----------
  Replace sequences of v.push_back(v[i]); v.erase(&v[i]); with std::rotate (NFC)

The code has a few sequence that looked like:

    Ops.push_back(Ops[0]);
    Ops.erase(Ops.begin());

And are equivalent to:

    std::rotate(Ops.begin(), Ops.begin() + 1, Ops.end());

The latter has the advantage of never reallocating the vector, which
would be a bug in the original code as push_back would read from the
memory it deallocated.


  Commit: 2c196bbc6bd897b3dcc1d87a3baac28e1e88df41
      https://github.com/llvm/llvm-project/commit/2c196bbc6bd897b3dcc1d87a3baac28e1e88df41
  Author: Mehdi Amini <joker.eph at gmail.com>
  Date:   2020-11-14 (Sat, 14 Nov 2020)

  Changed paths:
    M llvm/include/llvm/ADT/SmallVector.h
    M llvm/include/llvm/MC/MCInst.h

  Log Message:
  -----------
  Add an assertion in SmallVector::push_back()

This assertion ensures the input value isn't part of the vector when
growing is required. In such cases the vector will grow and the input
value is invalidated before being read from.

This found 14 failed Tests.

Reviewed By: bkramer

Differential Revision: https://reviews.llvm.org/D84293


Compare: https://github.com/llvm/llvm-project/compare/703ef17e7a0a...2c196bbc6bd8