• update according to comments

Add unit test.

• typo

Did you try "ninja check-all"? Everything ok?

This results in many ICmp Instructions to have completely wrong !dbg attached, since it points to a different subprogram.

ping!

• update to reflect the comments

In D49746#1174388, @hsaito wrote:

This is essentially a zero trip check for the remainder loop and from that perspective, the most correct DL we should use would be the one related to trip count computation. InnerLoopVectorizer::getOrCreateTripCount() is where LV computes the trip count of the incoming scalar loop. It uses getBackedgeTakeCount(). As such, strictly speaking, taking the DL from the predicate (i.e., loop bottom test) fed to the loop backedge would make most sense. That would be OrigLoop->getLoopLatch()->getTerminator() to get to the backedge. In a relaxed thinking, however, this is the code executed when we know vector code executes. So, taking DL from VectorPH code isn't too bad. OrigLoop->getStartLoc() could be another viable enough alternative.

Does this make sense to you? Which one would you pick?

• Update test according to comments.

Can there be multiple induction phis in the original loop's header? If so, why is picking the location from the first phi correct?

Adressing latest comments

• DebugLoc pass by value
• embed code in helper function

• styling nit

• Refactored the createInductionVariable() function to accept DebugLoc instead of Instruction.
• Get the debugLoc to set from the oldBasicBlock's induction variable if any.`

• minor styling changes

• change section title to reflect contents
• add note for robust tests

• Address inline comments.

Address inline comments.

Use exact line in test

• Code blocks had some whitespace
• Check that arc works with new dev envrionment

Make test more readable

typo in test

Addressing inline comments.

Formatting

If there isn't a simpler file to repurpose as a debug info test, it would be simpler to create a (perhaps more reduced?) test.

Address inline comments.

Incorporate the -debugify test into the existing test files.

Remove -instcombine from the RUN clause of the test.

Addressing the comments

• Update the scalar case according to the comments
• Postpone vector case for a later patch

• Focus on the scalar test case
• Use fragments since the width of the Src and Res instructions change

Fragments don't seem to be needed here

Update lamda to return nullptr if it fails to create the fragment.

Make use of rL335144 utility.

Clean up code and test

Add RUN: clause to the test

ping! should I commit this?

Make more elaborate comment.

make code more readable

What about this? Ping!

Add artificial debug location to the phi instruction

Add comment explaining the test