add LLVM_DSOLocalEquivalentAttr, change folder, add one more test

Author: bcardosolopes

mlir/include/mlir/Dialect/LLVMIR/LLVMAttrDefs.td

@@ -1213,6 +1213,17 @@ def LLVM_UndefAttr : LLVM_Attr<"Undef", "undef">;
 /// Folded into from LLVM::PoisonOp.
 def LLVM_PoisonAttr : LLVM_Attr<"Poison", "poison">;
 
+//===----------------------------------------------------------------------===//
+// DSOLocalEquivalentAttr
+//===----------------------------------------------------------------------===//
+
+/// Folded into from LLVM::DSOLocalEquivalentOp.
+def LLVM_DSOLocalEquivalentAttr : LLVM_Attr<"DSOLocalEquivalent",
+                                            "dso_local_equivalent"> {
+  let parameters = (ins "StringAttr":$name);
+  let assemblyFormat = "$name";
+}
+
 //===----------------------------------------------------------------------===//
 // VecTypeHintAttr
 //===----------------------------------------------------------------------===//

mlir/lib/Dialect/LLVMIR/IR/LLVMDialect.cpp

@@ -2167,9 +2167,11 @@ DSOLocalEquivalentOp::verifySymbolUses(SymbolTableCollection &symbolTable) {
   return success();
 }
 
-// DSOLocalEquivalentOp constant-folds to the global symbol name.
+/// Fold a dso_local_equivalent operation to a dedicated dso_local_equivalent
+/// attribute.
 OpFoldResult DSOLocalEquivalentOp::fold(FoldAdaptor) {
-  return getFunctionNameAttr();
+  return DSOLocalEquivalentAttr::get(getContext(),
+                                     getFunctionNameAttr().getAttr());
 }
 
 //===----------------------------------------------------------------------===//

mlir/test/Dialect/LLVMIR/constant-folding.mlir

@@ -182,3 +182,17 @@ func.func @insert_op(%arg0: index, %arg1: memref<13x13xi64>, %arg2: index) {
   vector.print %101 : vector<1xi64>
   return
 }
+
+// -----
+
+// CHECK-LABEL: llvm.func @dso_local_equivalent_select
+llvm.func @dso_local_equivalent_select(%arg: i1) -> !llvm.ptr {
+  // CHECK-NEXT: %[[DSOLOCALEQ:.+]] = llvm.dso_local_equivalent @yay
+  %0 = llvm.dso_local_equivalent @yay : !llvm.ptr
+  %1 = llvm.dso_local_equivalent @yay : !llvm.ptr
+  %2 = arith.select %arg, %0, %1 : !llvm.ptr
+  // CHECK-NEXT: llvm.return %[[DSOLOCALEQ]]
+  llvm.return %2 : !llvm.ptr
+}
+
+llvm.func @yay()