In D97828#2674875, @Whitney wrote:

@TaWeiTu How do you want to handle the lcssa.ll failure? Maybe we can only disallow memory accesses that are guarded by loop variant condition?

• Skip loop-invariant-guarded blocks

Ping

Ping

ping.

Gentle ping

The debug message and test description are improved in rG4d9d7368759

Hi Florian,

In D99252#2647105, @SjoerdMeijer wrote:

Yep, agreed, seems reasonable. Thanks for fixing.

Thanks for the review!

In D98548#2625593, @tmatheson wrote:

This seems quite an early point to bail out, so it will prevent some errors/warnings associated with initialization from being emitted. For example, this warning is currently emitted but would be suppressed by this patch:

union {
  virtual int a();
  int b = 'c'; // expected-warning {{in-class initialization of non-static data member is a C++11 extension [-Wc++11-extensions]}}
}

I don't know how much that matters seeing as the union is invalid by this point.

In D97828#2624775, @Whitney wrote:

Have you considered the case where the blocks guarded by control flow doesn't have memory operation, but affect memory operation through phi?

bb1:
  br %cond, bb2, bb3
bb2:
  br bb4
bb3:
  br bb4
bb4:
  %t = phi [ %t2, %bb2 ], [ %t3, %bb3 ]
  store %t, %p

Consider instructions that are indirectly affected by the control flow

ping

In D98144#2623484, @rupprecht wrote:

Reverted in 8d20f2c2c66eb486ff23cc3d55a53bd840b36971. Although this fixes a crash, it also introduces a compile timeout (haven't checked if it's a true infinite loop or just _really_ slow) on other code. The reproducer is in the commit message.

I'm not familiar with this code and clang/sema in general, so not sure if the fix makes sense.

Hi @congzhe, thanks for the fix!

In D98263#2617156, @Whitney wrote:

The patch now revert part of https://reviews.llvm.org/rGdf9158c9a45a6902c2b0394f9bd6512e3e441f31, which leave some changes behind.
Given that the change cause a test case crash, @TaWeiTu can you please revert the change?

• Fix test

Thanks for the review!

• Fix nits

• Add TODOs

• Fix typo

• Add testcase

• Only check basic blocks in the inner loop

• Remove isTotallyNested

• Use LoopInfo::getLoopFor

• Fix nits

• Add LoopInterchange for O1 as well

• Add testcase of PR47523

The following test in lcssa.ll is failing:

In D97828#2607047, @fhahn wrote:

Is this fixing a similar issue to D91228 /D87879?

• Remove unnecessary lines in the test case

• Remove unnecessary lines in the test case

Gentle ping.

Trigger rebuild

• Move #ifndef NDEBUG guard
• Reduce bug reproducer

Rebase

Copy reproducer from bugzilla.
Will try to minimize it later.

Replace LoopNest::getHeader() with LoopNest::getParent()

Rebase on top of D96650