[PATCH] D109015: [SCEV] If max BTC is zero, then so is the exact BTC [2 of 2]

[Nikita Popov via Phabricator via llvm-commits]

nikic accepted this revision.
nikic added a subscriber: SjoerdMeijer.
nikic added a comment.
This revision is now accepted and ready to land.

LGTM



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Comment at: llvm/lib/Target/ARM/MVETailPredication.cpp:305
+    // reasoning, and our RHS just above doesn't.
+    Sub = SE->applyLoopGuards(Sub, L);
+
----------------
reames wrote:
> nikic wrote:
> > Any chance evaluating an EQ predicate with one of our context sensitive functions (like isLoopEntryGuardedBy) would also work here? Calling applyLoopGuards() here is rather tightly coupled to SCEV implementation details.
> I don't believe we can here without changing the cases this can and can't handle more than I'm comfortable with.  I don't understand this code - the comments appears to be out of sync with what it actually does - so I'd strongly prefer to keep it as close to the original structure as possible.  
Okay, let's land this as-is. But maybe @dmgreen or @SjoerdMeijer can take a look at this code and check whether it's possible to avoid doing this.


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  https://reviews.llvm.org/D109015/new/

https://reviews.llvm.org/D109015