Max Kazantsev a3d1fb3b59 [SCEV] Prove condition invariance via context ...

Contextual knowledge may be used to prove invariance of some conditions.
For example, in this case:
```
  ; %len >= 0
  guard(%iv = {start,+,1}<nuw> <s %len)
  guard(%iv = {start,+,1}<nuw> <u %len)
```
the 2nd check always fails if `start` is negative and always passes otherwise.

It looks like there are more opportunities of this kind that are still to be
implemented in the future.

Differential Revision: https://reviews.llvm.org/D129753
Reviewed By: apilipenko

2022-08-12 14:23:35 +07:00

42 KiB

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