[llvm] llvm-reduce: Avoid removing convergent with convergence tokens (PR #132946)

[Matt Arsenault via llvm-commits]

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@@ -44,9 +44,25 @@ namespace {
 class AttributeRemapper : public InstVisitor<AttributeRemapper> {
   Oracle &O;
   LLVMContext &Context;
+  bool HasControlledConvergence = true;
 
 public:
-  AttributeRemapper(Oracle &O, LLVMContext &C) : O(O), Context(C) {}
+  AttributeRemapper(Oracle &O, Module &M) : O(O), Context(M.getContext()) {
+
+    // Check if there are any convergence intrinsics used. We cannot remove the
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arsenm wrote:

The point of the reduction is not remove the attribute at any cost. Any change in the reproducer is more likely related to the side effect of hacking on the actual instructions, not the attribute removal. It's not written to do so, nor should it be. Attributes that impose structural restrictions on the IR are problematic. It is fine to just ignore it. 

https://github.com/llvm/llvm-project/pull/132946