tree b4e0f17eef685112fd41789c77499815ffbe0645
parent 5ec91b392d7ea7991052892c79e0b315ab54f3c4
author Nikita Popov <npopov@redhat.com> 1716443648 +0200
committer GitHub <noreply@github.com> 1716443648 +0200
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[SCEV] Support ule/sle exit counts via widening (#92206)

If we have an exit condition of the form IV <= Limit, we will first try
to convert it into IV < Limit+1 or IV-1 < Limit based on range info (in
icmp simplification). If that fails, we try to convert it to IV < Limit
+ 1 based on controlling exits in non-infinite loops.

However, if all else fails, we can still determine the exit count by
rewriting to ext(IV) < ext(Limit) + 1, where the zero/sign extension
ensures that the addition does not overflow.

Proof: https://alive2.llvm.org/ce/z/iR-iYd