[llvm] [LoopFusion] Fix sink instructions (PR #147501)

[Madhur Amilkanthwar via llvm-commits]

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@@ -1176,6 +1176,27 @@ struct LoopFuser {
     return true;
   }
 
+  // This function fixes sunk PHI nodes after fusion.
+  void fixPHINodes(SmallVector<Instruction *, 4> &SafeToSink,
+                   const FusionCandidate &FC0,
+                   const FusionCandidate &FC1) const {
+    // Iterate over SafeToSink instructions and update PHI nodes
+    // to take values from the latch block of FC0 if they are taking
+    // from the latch block of FC1.
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madhur13490 wrote:

Added more description.

https://github.com/llvm/llvm-project/pull/147501