[mlir][llvm] Handle llvm.noundef attribute when converting to LLVM IR

Translate LLVMIR llvm.noundef attribute to its equivalent in LLVM IR.

Reviewed By: ftynse

Differential Revision: https://reviews.llvm.org/D136324

diff --git a/mlir/include/mlir/Dialect/LLVMIR/LLVMOpBase.td b/mlir/include/mlir/Dialect/LLVMIR/LLVMOpBase.td
index 8f63e98..e4f9299 100644 (file)
--- a/mlir/include/mlir/Dialect/LLVMIR/LLVMOpBase.td
+++ b/mlir/include/mlir/Dialect/LLVMIR/LLVMOpBase.td
@@ -49,6 +49,7 @@ def LLVM_Dialect : Dialect {
     static StringRef getByRefAttrName() { return "llvm.byref"; }
     static StringRef getStructRetAttrName() { return "llvm.sret"; }
     static StringRef getInAllocaAttrName() { return "llvm.inalloca"; }
+    static StringRef getNoUndefAttrName() { return "llvm.noundef"; }
 
     /// Verifies if the attribute is a well-formed value for "llvm.struct_attrs"
     static LogicalResult verifyStructAttr(

diff --git a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
index 1503611..26bc99f 100644 (file)
--- a/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
+++ b/mlir/lib/Target/LLVMIR/ModuleTranslation.cpp
@@ -917,6 +917,13 @@ LogicalResult ModuleTranslation::convertOneFunction(LLVMFuncOp func) {
                            .addAttribute(llvm::Attribute::Nest));
     }
 
+    if (auto attr = func.getArgAttrOfType<UnitAttr>(
+            argIdx, LLVMDialect::getNoUndefAttrName())) {
+      // llvm.noundef can be added to any argument type.
+      llvmArg.addAttrs(llvm::AttrBuilder(llvmArg.getContext())
+                           .addAttribute(llvm::Attribute::NoUndef));
+    }
+
     mapValue(mlirArg, &llvmArg);
     argIdx++;
   }

diff --git a/mlir/test/Target/LLVMIR/llvmir.mlir b/mlir/test/Target/LLVMIR/llvmir.mlir
index 5153874..5a13e86 100644 (file)
--- a/mlir/test/Target/LLVMIR/llvmir.mlir
+++ b/mlir/test/Target/LLVMIR/llvmir.mlir
@@ -1064,6 +1064,11 @@ llvm.func @nestattr(%arg0: !llvm.ptr<i32> {llvm.nest}) {
   llvm.return
 }
 
+// CHECK-LABEL: define void @noundefattr(i32 noundef %
+llvm.func @noundefattr(%arg0: i32 {llvm.noundef}) {
+  llvm.return
+}
+
 // CHECK-LABEL: define void @llvm_align(ptr align 4 {{%*.}})
 llvm.func @llvm_align(%arg0: !llvm.ptr<f32> {llvm.align = 4}) {
   llvm.return