[IndVars] Add a todo to reflect a further oppurtunity identified in D69009
Nikita pointed out an oppurtunity, might as well document it in the code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@375380 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp
index 2981c14..295e072 100644
--- a/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -2794,6 +2794,13 @@
Changed = true;
continue;
}
+
+ // TODO: There might be another oppurtunity to leverage SCEV's reasoning
+ // here. If we kept track of the min of dominanting exits so far, we could
+ // discharge exits with EC >= MDEC. This is less powerful than the existing
+ // transform (since later exits aren't considered), but potentially more
+ // powerful for any case where SCEV can prove a >=u b, but neither a == b
+ // or a >u b. Such a case is not currently known.
}
return Changed;
}
