Add region predication to output tracer

jlm/llvm/ir/Trace.cpp

@@ -28,33 +28,39 @@ OutputTracer::OutputTracer()
     : rvsdg::OutputTracer()
 {}
 
-rvsdg::Output &
-OutputTracer::traceStep(rvsdg::Output & output, const rvsdg::Region * withinRegion)
+OutputTracer::TraceStepResult
+OutputTracer::traceStep(
+    rvsdg::Output & output,
+    BackEdgeState backEdgeState,
+    const rvsdg::Region * withinRegion)
 {
-  auto & trace1 = rvsdg::OutputTracer::traceStep(output, withinRegion);
+  const auto trace1 = rvsdg::OutputTracer::traceStep(output, backEdgeState, withinRegion);
+  auto & trace1Output = trace1.getOutput();
 
   if (const auto [node, ioBarrierOp] =
-          rvsdg::TryGetSimpleNodeAndOptionalOp<IOBarrierOperation>(trace1);
+          rvsdg::TryGetSimpleNodeAndOptionalOp<IOBarrierOperation>(trace1Output);
       node && ioBarrierOp)
   {
-    return *IOBarrierOperation::BarredInput(*node).origin();
+    return TraceStepResult::createStepResult(*IOBarrierOperation::BarredInput(*node).origin());
   }
 
   // If enabled, try tracing through the memory states of load nodes
   if (traceThroughLoadedStates_)
   {
-    if (const auto [node, loadOp] = rvsdg::TryGetSimpleNodeAndOptionalOp<LoadOperation>(trace1);
+    if (const auto [node, loadOp] =
+            rvsdg::TryGetSimpleNodeAndOptionalOp<LoadOperation>(trace1Output);
         node && loadOp)
     {
-      if (is<MemoryStateType>(trace1.Type()))
+      if (is<MemoryStateType>(trace1Output.Type()))
       {
         // Map the memory state output to the corresponding memory state input
-        auto & memoryStateInput = LoadOperation::MapMemoryStateOutputToInput(trace1);
-        return *memoryStateInput.origin();
+        auto & memoryStateInput = LoadOperation::MapMemoryStateOutputToInput(trace1Output);
+        return TraceStepResult::createStepResult(*memoryStateInput.origin());
       }
     }
   }
 
+  // We were not able to make any extra progress on the trace result, so return it as is
   return trace1;
 }
 
@@ -66,6 +72,7 @@ traceOutput(rvsdg::Output & output, bool mayEnterSubregions, const rvsdg::Region
       mayEnterSubregions
           ? rvsdg::OutputTracer::StructuralNodePolicy::traceIntoSubregions
           : rvsdg::OutputTracer::StructuralNodePolicy::traceThroughIfDetectedInvariant);
+  tracer.setRegionPredicateCheckingEnabled(mayEnterSubregions);
   tracer.setEnterPhiNodes(mayEnterSubregions);
   return tracer.trace(output, withinRegion);
 }

jlm/llvm/ir/Trace.hpp

@@ -42,8 +42,9 @@ class OutputTracer : public rvsdg::OutputTracer
   }
 
 protected:
-  [[nodiscard]] rvsdg::Output &
-  traceStep(rvsdg::Output & output, const rvsdg::Region * withinRegion) override;
+  [[nodiscard]] TraceStepResult
+  traceStep(rvsdg::Output & output, BackEdgeState backEdgeState, const rvsdg::Region * withinRegion)
+      override;
 
 private:
   bool traceThroughLoadedStates_ = false;

jlm/llvm/opt/alias-analyses/AliasAnalysisPrecisionEvaluator.hpp

@@ -14,11 +14,6 @@
 
 #include <unordered_map>
 
-namespace jlm::util
-{
-class GraphWriter;
-}
-
 namespace jlm::llvm::aa
 {