[llvm] [IndVarSimplify] Fix `IndVarSimplify` to skip on unfolding predicates when the loop contains control convergence operations. (PR #165643)

[Steven Perron via llvm-commits]

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@@ -1859,6 +1860,18 @@ bool IndVarSimplify::predicateLoopExits(Loop *L, SCEVExpander &Rewriter) {
         }
       }
 
+  CodeMetrics Metrics;
+  SmallPtrSet<const Value *, 32> EphValues;
+  for (BasicBlock *BB : L->blocks()) {
+    Metrics.analyzeBasicBlock(BB, *TTI, EphValues, /* PrepareForLTO= */ false,
+                              L);
+  }
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s-perron wrote:

This might be overkill. I believe the convergence token has to be defined in the loop header. The code metics does more than is needed. However, you can use the code in codemetrics.cpp as a guide on how to implement what is needed in this pass.

https://github.com/llvm/llvm-project/pull/165643