[PATCH] D35010: [IRCE] Recognize loops with ne/eq latch conditions

[Sanjoy Das via Phabricator via llvm-commits]

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Did you consider a somewhat more general trick of using the loop's BE taken count to derive an equivalent BE condition?  E.g. if the loops be taken count is 100, and the post-incremented indvar (the one the BE condition uses) is `{5,+,1}` (everything is `i32`) then the BE taken condition can be `++I s< 105` (and you can derive this without looking at whether the BE condition was expressed using SLT or NE or EQ etc.).



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Comment at: lib/Transforms/Scalar/InductiveRangeCheckElimination.cpp:810
+    if (Pred == ICmpInst::ICMP_NE && LatchBrExitIdx == 1)
+      // while (++i != len) {         while (++i < len) {
+      //   ...                 --->     ...
----------------
I don't think this equivalence holds if the RHS is negative.


https://reviews.llvm.org/D35010