[llvm] change contents of ScalarEvolution from private to protected (PR #83052)

[William Moses via llvm-commits]

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@@ -0,0 +1,70 @@
+
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/LoopAnalysisManager.h"
+#include "llvm/Analysis/TargetLibraryInfo.h"
+
+#include "llvm/IR/Function.h"
+
+#include "llvm/IR/Instructions.h"
+#include "llvm/Transforms/Utils/ValueMapper.h"
+#include <deque>
+
+// TODO note this doesn't go through [loop, unreachable], and we could get more
+// performance by doing this can consider doing some domtree magic potentially
+static inline llvm::SmallPtrSet<llvm::BasicBlock *, 4>
+getGuaranteedUnreachable(llvm::Function *F) {
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wsmoses wrote:

In the context of SE, I think the best way to integrate this may be a list of blocks/branches/etc for SE to ignore in the context of computing the available exits.

In this context we're choosing ones that are guaranteed to hit unreachable, but I think the nicer one to integrate would be something along the lines of `IgnoredExitingBlocks`. Of course to properly test this we may need to still have a version of getUnreachable somewhere to build a version of the SE exiting for loop test, but that way SE remains general

https://github.com/llvm/llvm-project/pull/83052