fix noalias test, add addressof op

enzyme/Enzyme/MLIR/Analysis/DataFlowActivityAnalysis.cpp

@@ -34,6 +34,7 @@
 #include "mlir/Analysis/DataFlow/DenseAnalysis.h"
 #include "mlir/Analysis/DataFlow/SparseAnalysis.h"
 #include "mlir/Analysis/DataFlowFramework.h"
+#include "mlir/IR/Matchers.h"
 #include "mlir/Interfaces/SideEffectInterfaces.h"
 
 // TODO: Don't depend on specific dialects
@@ -856,7 +857,7 @@ void printActivityAnalysisResults(const DataFlowSolver &solver,
  });
  };
 
- if (isa_and_present<LLVM::PoisonOp, LLVM::ZeroOp>(
+ if (isa_and_present<LLVM::PoisonOp, LLVM::ZeroOp, LLVM::AddressOfOp>(
  value.getDefiningOp())) {
  // Alias classes aren't computed for poison ops, but they are
  // definitionally constant.
@@ -867,6 +868,7 @@ void printActivityAnalysisResults(const DataFlowSolver &solver,
  // TODO: We're seeing a case where we load from calloc which is
  // defined to be zero.
  errs() << "ac for " << value << " was undefined\n";
+ return true;
  }
  // If this triggers, investigate why the alias classes weren't computed.
  // If they weren't computed legitimately, treat the value as

enzyme/test/MLIR/AliasAnalysis/llvm_noalias.mlir

@@ -1,10 +1,11 @@
 // RUN: %eopt --test-print-alias-analysis --split-input-file %s 2>&1 | FileCheck %s
 
 // The dataflow framework never sees what is stored into %x, but we know its load result does not alias
-// with anything else in the function because it has `noalias`.
+// with %x itself because of the `llvm.noalias`
 
 // CHECK: "x" and "x_load": NoAlias
-llvm.func @f(%x: !llvm.ptr {enzyme.tag = "x", llvm.noalias}) {
+// CHECK: "y" and "x_load": MayAlias
+llvm.func @f(%x: !llvm.ptr {enzyme.tag = "x", llvm.noalias}, %y: !llvm.ptr {enzyme.tag = "y"}) {
  %x_load = llvm.load %x {tag = "x_load"} : !llvm.ptr -> !llvm.ptr
  llvm.return
 }