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

[Sameer Sahasrabuddhe 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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ssahasra wrote:

Why not strip the control token along with the convergent attribute? The only place you can't strip a token is when it is the operand of the loop intrinsic, unless previous reductions make the loop intrinsic itself unused and it can be eliminated entirely.

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