[mlir][llvmir] Add support for llvm.signext/zeroext function attributes.

This change-set adds basic support for llvm.signext and llvm.zeroext
attributes, and makes sure that the attributes are translated to LLVM IR
when attached to arguments.

This is needed for llvm#58579

Differential Revision: https://reviews.llvm.org/D137048

Author: vzakhari

mlir/include/mlir/Dialect/LLVMIR/LLVMOpBase.td

@@ -49,6 +49,8 @@ def LLVM_Dialect : Dialect {
     static StringRef getStructRetAttrName() { return "llvm.sret"; }
     static StringRef getInAllocaAttrName() { return "llvm.inalloca"; }
     static StringRef getNoUndefAttrName() { return "llvm.noundef"; }
+    static StringRef getSExtAttrName() { return "llvm.signext"; }
+    static StringRef getZExtAttrName() { return "llvm.zeroext"; }
 
     /// Verifies if the attribute is a well-formed value for "llvm.struct_attrs"
     static LogicalResult verifyStructAttr(

mlir/lib/Target/LLVMIR/ModuleTranslation.cpp

@@ -984,6 +984,25 @@ LogicalResult ModuleTranslation::convertFunctionSignatures() {
         llvmArg.addAttrs(llvm::AttrBuilder(llvmArg.getContext())
                              .addAttribute(llvm::Attribute::NoUndef));
       }
+      if (auto attr = function.getArgAttrOfType<UnitAttr>(
+              argIdx, LLVMDialect::getSExtAttrName())) {
+        // llvm.signext can be added to any integer argument type.
+        if (!mlirArgTy.isa<mlir::IntegerType>())
+          return function.emitError(
+              "llvm.signext attribute attached to LLVM non-integer argument");
+        llvmArg.addAttrs(llvm::AttrBuilder(llvmArg.getContext())
+                             .addAttribute(llvm::Attribute::SExt));
+      }
+      if (auto attr = function.getArgAttrOfType<UnitAttr>(
+              argIdx, LLVMDialect::getZExtAttrName())) {
+        // llvm.zeroext can be added to any integer argument type.
+        if (!mlirArgTy.isa<mlir::IntegerType>())
+          return function.emitError(
+              "llvm.zeroext attribute attached to LLVM non-integer argument");
+        llvmArg.addAttrs(llvm::AttrBuilder(llvmArg.getContext())
+                             .addAttribute(llvm::Attribute::ZExt));
+      }
+
       ++argIdx;
     }
 

mlir/test/Target/LLVMIR/llvmir-invalid.mlir

@@ -83,6 +83,20 @@ llvm.func @invalid_align(%arg0 : f32 {llvm.align = 4}) -> f32 {
 
 // -----
 
+// expected-error @below{{llvm.signext attribute attached to LLVM non-integer argument}}
+llvm.func @invalid_signext(%arg0: f32 {llvm.signext}) {
+  "llvm.return"() : () -> ()
+}
+
+// -----
+
+// expected-error @below{{llvm.zeroext attribute attached to LLVM non-integer argument}}
+llvm.func @invalid_zeroext(%arg0: f32 {llvm.zeroext}) {
+  "llvm.return"() : () -> ()
+}
+
+// -----
+
 llvm.func @no_non_complex_struct() -> !llvm.array<2 x array<2 x array<2 x struct<(i32)>>>> {
   // expected-error @below{{expected struct type to be a complex number}}
   %0 = llvm.mlir.constant(dense<[[[1, 2], [3, 4]], [[42, 43], [44, 45]]]> : tensor<2x2x2xi32>) : !llvm.array<2 x array<2 x array<2 x struct<(i32)>>>>

mlir/test/Target/LLVMIR/llvmir.mlir

@@ -1108,6 +1108,22 @@ llvm.func @inallocaattr(%arg0: !llvm.ptr<i32> {llvm.inalloca = i32}) {
 // CHECK-LABEL: declare void @inallocaattr_decl(ptr inalloca(i32))
 llvm.func @inallocaattr_decl(!llvm.ptr<i32> {llvm.inalloca = i32})
 
+// CHECK-LABEL: define void @signextattr(i1 signext %
+llvm.func @signextattr(%arg0: i1 {llvm.signext}) {
+  llvm.return
+}
+
+// CHECK-LABEL: declare void @signextattr_decl(i1 signext)
+llvm.func @signextattr_decl(i1 {llvm.signext})
+
+// CHECK-LABEL: define void @zeroextattr(i1 zeroext %
+llvm.func @zeroextattr(%arg0: i1 {llvm.zeroext}) {
+  llvm.return
+}
+
+// CHECK-LABEL: declare void @zeroextattr_decl(i1 zeroext)
+llvm.func @zeroextattr_decl(i1 {llvm.zeroext})
+
 // CHECK-LABEL: @llvm_varargs(...)
 llvm.func @llvm_varargs(...)