[llvm] [SCEV] Collect and merge loop guards through PHI nodes with multiple incoming values (PR #113915)

[Florian Hahn via llvm-commits]

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@@ -1316,6 +1316,25 @@ class ScalarEvolution {
 
     LoopGuards(ScalarEvolution &SE) : SE(SE) {}
 
+    /// Recursively collect loop guards in \p Guards, starting from
+    /// block \p Block with predecessor \p Pred. The intended starting point
+    /// is to collect from a loop header and its predecessor.
+    static void
+    collectFromBlock(ScalarEvolution &SE, ScalarEvolution::LoopGuards &Guards,
+                     const BasicBlock *Block, const BasicBlock *Pred,
+                     SmallPtrSetImpl<const BasicBlock *> &VisitedBlocks,
+                     unsigned Depth = 0);
+
+    /// Collect loop guards in \p Guards, starting from PHINode \p
+    /// Phi, by calling \p collectFromBlock on the incoming blocks of
+    /// \Phi and trying to merge the found constraints into a single
+    /// combined on for \p Phi.
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fhahn wrote:

Should be fixed in feb9b3701bf6650f91e12e7f4efbe72383f3f60b (@juliannagele is OOO for few days, so I took care of it)

https://github.com/llvm/llvm-project/pull/113915