[llvm] [SimplifyCFG] Supporting hoisting/sinking callbases with differing attrs (PR #109472)

[via llvm-commits]

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@@ -1591,10 +1591,150 @@ static void hoistLockstepIdenticalDbgVariableRecords(
   }
 }
 
+// See if we can intersect the attributes for two callbases (used for
+// hoisting/sinking).
+static std::optional<AttributeList> tryIntersectAttrs(const CallBase *CB0,
+                                                      const CallBase *CB1) {
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goldsteinn wrote:

Thats what I originally had done, the reason I changed it was the sink/hoist intersection isn't necessarily complete as there may be attributes that change the nature of a function to a degree that makes sinking/hoisting no profitable i.e you can imagine something like the alloc attributes which are probably best not to drop.

https://github.com/llvm/llvm-project/pull/109472