[flang][lowering] Add support for lowering of the `ior` intrinsic

[awarzynski]

Summary

This patch adds support for lowering of the ior intrinsic from
Fortran to the FIR dialect of MLIR.

This is part of the upstreaming effort from the fir-dev branch in [1].

[1] https://github.com/flang-compiler/f18-llvm-project

Co-authored-by: Jean Perier <[e-mail]>
Co-authored-by: V Donaldson <[e-mail]>
Co-authored-by: Eric Schweitz <[e-mail]>

[schweitz]

Note: The test should be extended to exercise the elemental aspect of IOR when that gets upstreamed as well.

flang/lib/Lower/IntrinsicCall.cpp

struct IntrinsicLibrary {
   /// in the llvm::ArrayRef.
   mlir::Value genIand(mlir::Type, llvm::ArrayRef<mlir::Value>);
   mlir::Value genIbclr(mlir::Type, llvm::ArrayRef<mlir::Value>);
   mlir::Value genIbits(mlir::Type, llvm::ArrayRef<mlir::Value>);
   mlir::Value genIbset(mlir::Type, llvm::ArrayRef<mlir::Value>);
   fir::ExtendedValue genIchar(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
   mlir::Value genIeor(mlir::Type, llvm::ArrayRef<mlir::Value>);
   fir::ExtendedValue genIndex(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
+  mlir::Value genIor(mlir::Type, llvm::ArrayRef<mlir::Value>);
   mlir::Value genIshft(mlir::Type, llvm::ArrayRef<mlir::Value>);
   mlir::Value genIshftc(mlir::Type, llvm::ArrayRef<mlir::Value>);
   fir::ExtendedValue genLbound(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
   fir::ExtendedValue genLen(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
   fir::ExtendedValue genLenTrim(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
   fir::ExtendedValue genMatmul(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
   fir::ExtendedValue genMaxloc(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
   fir::ExtendedValue genMaxval(mlir::Type, llvm::ArrayRef<fir::ExtendedValue>);
static constexpr IntrinsicHandler handlers[]{
     {"ichar", &I::genIchar},
     {"ieor", &I::genIeor},
     {"index",
      &I::genIndex,
      {{{"string", asAddr},
        {"substring", asAddr},
        {"back", asValue, handleDynamicOptional},
        {"kind", asValue}}}},
+    {"ior", &I::genIor},
     {"ishft", &I::genIshft},
     {"ishftc", &I::genIshftc},
     {"lbound",
      &I::genLbound,
      {{{"array", asInquired}, {"dim", asValue}, {"kind", asValue}}},
      /*isElemental=*/false},
     {"len",
      &I::genLen,
IntrinsicLibrary::genIndex(mlir::Type resultType,
   mlir::Value resBox = fir::factory::getMutableIRBox(builder, loc, mutBox);
   // Call runtime. The runtime is allocating the result.
   fir::runtime::genIndexDescriptor(builder, loc, resBox, string, substring,
                                    backOpt, kindVal);
   // Read back the result from the mutable box.
   return readAndAddCleanUp(mutBox, resultType, "INDEX");
 }
 
+// IOR
+mlir::Value IntrinsicLibrary::genIor(mlir::Type resultType,
+                                     llvm::ArrayRef<mlir::Value> args) {
+  assert(args.size() == 2);
+  return builder.create<mlir::arith::OrIOp>(loc, args[0], args[1]);
+}
+
 // ISHFT
 mlir::Value IntrinsicLibrary::genIshft(mlir::Type resultType,
                                        llvm::ArrayRef<mlir::Value> args) {
   // A conformant ISHFT(I,SHIFT) call satisfies:
   //     abs(SHIFT) <= BIT_SIZE(I)
   // Return:  abs(SHIFT) >= BIT_SIZE(I)
   //              ? 0
   //              : SHIFT < 0

flang/test/Lower/Intrinsics/ior.f90

+! RUN: bbc -emit-fir %s -o - | FileCheck %s
+! RUN: %flang_fc1 -emit-fir %s -o - | FileCheck %s
+
+! CHECK-LABEL: ior_test
+subroutine ior_test(a, b)
+  integer :: a, b
+  print *, ior(a, b)
+  ! CHECK: %{{[0-9]+}} = arith.ori %{{[0-9]+}}, %{{[0-9]+}} : i{{(8|16|32|64|128)}}
+end subroutine ior_test
+