Summary:
This change adds a framework for adding more smarts to
`isImpliedCondition` around inequalities. Informally,
`isImpliedCondition` will now try to prove "A < B ==> C < D" by proving
"C <= A && B <= D", since then it follows "C <= A < B <= D".
While this change is in principle NFC, I could not think of a way to not
handle cases like "i +_nsw 1 < L ==> i < L +_nsw 1" (that ValueTracking
did not handle before) while keeping the change understandable. I've
added tests for these cases.
Reviewers: reames, majnemer, hfinkel
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D14368
llvm-svn: 252331
f52081da0a